test(crm): HTTP route tests for CRM public + admin surface (#570)

Closes #570.

PR #555 shipped the CRM module with strong service-layer coverage
but no HTTP-layer tests. This adds Supertest-based route coverage
across the externally-reachable public routes (P0) and an auth-gate
sweep of every CRM admin route (P1+P2).

## What's covered

### P0 — Public routes (49% of new tests)

The three public routes are the security-sensitive surface — any IP
with the raw token from a leaked email can hit them. Tests pin the
publicTokenGuards.loadActionToken contract end-to-end:

- **publicQuotes** (8 tests) — GET load + POST respond: 404 unknown,
  400 malformed, 410 expired, 200 valid w/ sanitised payload (no
  customer_account_id / created_by_admin_id leakage), 429 after 20
  bad attempts (IP lockout), 400 invalid action.
- **publicContracts** (10 tests) — GET load + POST sign + POST
  upload-signed-pdf + GET pdf: same guard outcomes per endpoint,
  plus the pre-multer token check (malformed token rejected before
  multer reads the body — prevents the disk-spam attack the
  preMulterTokenGuard was added for).
- **publicPaymentCheck** (6 tests) — different shape (no
  loadActionToken; service does its own validation): validator gate
  on token shape, all 4 canonical actions pass through the
  validator, negative amountMinor rejected.

The NULL-expires_at defensive branch in loadActionToken is
documented but not tested here — current schema declares
quote/contract_action_tokens.expires_at NOT NULL, so the branch is
unreachable at the route level. Worth a direct unit test on
loadActionToken if anyone wants to cover it.

### P1 + P2 — Admin routes (51% of new tests, 25 cases)

One consolidated `adminCrmAuth.test.js` file rather than nine
per-route files — the auth-gate contract is identical for every CRM
admin route, so a parametrised `describe.each` is more efficient
and lands the same coverage:

Per route (adminQuotes, adminContracts, adminInvoices, adminCalendar,
adminDeals, adminTaxReport, adminBusinessProfile):
- 401 without Authorization header (adminAuth gate)
- 401 with invalid JWT signature (adminAuth signature check)
- 2xx with super-admin token + CRM feature flags on (permission +
  feature-flag gates both pass)

Plus 4 tests for the CRM additions in adminCustomers
(hour-entries / bill / trigger-monthly-bill) — those endpoints
are mixed in with pre-existing customer routes, so they get
explicit coverage rather than bulk via the parametrised sweep.

## Harness extensions to integration/helpers/crmDb.js

Three new helpers (one place for any future route test to find):

- `mintAdminToken(adminId, opts)` — JWT signed with the test
  JWT_SECRET, shape matches what adminAuth expects.
- `createPublicToken(db, tableName, opts)` — insert a row into
  quote/contract_action_tokens with controllable expires_at /
  used_at / token. Note: Date values are explicitly ISO-stringified
  before insert — bare Date objects round-tripped inconsistently
  through knex+SQLite, sometimes via .toString() → literal
  `"[object Object]"` which parsed back to NaN and silently defeated
  the expiry guard. Caught it in test bring-up.
- `buildRouteApp(mount, router)` — minimal Express app (json + cookies)
  with a catch-all error handler that mirrors middleware/errorHandler
  (uses err.statusCode, not err.status — getting that wrong silently
  maps every 4xx to 500 in tests).
- `assignAdminRole(db, adminId, roleName)` — promotes a seedMinimal
  admin into super_admin (or any seeded role) for happy-path tests.

## Out of scope (follow-up)

Deeper integration tests for the document mint/send paths
(adminQuotes.send → PDF persisted + token minted + email queued;
adminInvoices.Storno → new row with shared deal_uuid + original
cancelled; adminContracts.countersign → integrity_hash computed)
are deferred. The service-layer behind those is already covered by
the existing __tests__/services/ suites — this PR pins the
HTTP-layer contract, which is what #570 actually asked for.

## Counts

- 4 new test files, 49 tests total
- ~860 LOC of test code + ~85 LOC of new harness in crmDb.js
- All tests pass in <2.5s (no real network, no real disk except the
  per-test tmpdir, no email sending)

backend/__tests__/integration/helpers/crmDb.js

@@ -118,4 +118,113 @@ async function seedMinimal(db) {
   return { adminId, customerId };
 }
 
-module.exports = { bootCrmDb, seedMinimal };
+// ---------------------------------------------------------------------
+// Route-test helpers (#570) — building blocks for the CRM HTTP layer
+// tests. Kept here so every supertest suite shares the same minting +
+// app-wiring shape and a refactor lands in one place.
+// ---------------------------------------------------------------------
+
+const crypto = require('crypto');
+const jwt = require('jsonwebtoken');
+const express = require('express');
+const cookieParser = require('cookie-parser');
+
+/**
+ * Promote a seeded admin into a role (default `super_admin`) so
+ * `requirePermission(...)` checks pass. seedMinimal creates an admin
+ * without a role — that's good for negative tests (expect 403) but
+ * happy-path tests need the role assignment.
+ *
+ * Returns the role id the admin was assigned to.
+ */
+async function assignAdminRole(db, adminId, roleName = 'super_admin') {
+  const role = await db('roles').where({ name: roleName }).first();
+  if (!role) {
+    throw new Error(`Role '${roleName}' not seeded — check the test DB`);
+  }
+  await db('admin_users').where({ id: adminId }).update({ role_id: role.id });
+  return role.id;
+}
+
+/**
+ * Mint an admin JWT in the same shape adminAuth middleware expects.
+ * The tests inject this via `Authorization: Bearer <token>`.
+ */
+function mintAdminToken(adminId, { expiresIn = '1h', extraClaims = {} } = {}) {
+  process.env.JWT_SECRET = process.env.JWT_SECRET || 'crm-route-test-secret';
+  return jwt.sign(
+    { id: adminId, type: 'admin', iat: Math.floor(Date.now() / 1000), ...extraClaims },
+    process.env.JWT_SECRET,
+    { expiresIn, issuer: 'picpeak-auth' }
+  );
+}
+
+/**
+ * Insert a row into one of the public-token tables for testing the
+ * loadActionToken guard outcomes. Returns the generated 64-hex token.
+ *
+ * Usage:
+ *   await createPublicToken(db, 'quote_action_tokens', { quote_id: q.id });
+ *   await createPublicToken(db, 'quote_action_tokens', { quote_id: q.id, expires_at: pastDate });
+ *   await createPublicToken(db, 'quote_action_tokens', { quote_id: q.id, used_at: new Date() });
+ *   await createPublicToken(db, 'quote_action_tokens', { quote_id: q.id, expires_at: null });
+ */
+async function createPublicToken(db, tableName, opts = {}) {
+  const token = opts.token || crypto.randomBytes(32).toString('hex');
+  const expiresAt = opts.expires_at === null
+    ? null
+    : (opts.expires_at || new Date(Date.now() + 7 * 24 * 60 * 60 * 1000));
+  // Serialise Date → ISO string. Bare Date objects round-tripped
+  // inconsistently through knex+SQLite — sometimes as epoch ms,
+  // sometimes via .toString() → literal "[object Object]" which then
+  // parses back to NaN and silently defeats the expiry guard.
+  const toStorable = (v) => (v instanceof Date ? v.toISOString() : v);
+  const row = {
+    ...opts,
+    token,
+    expires_at: toStorable(expiresAt),
+    created_at: toStorable(new Date()),
+  };
+  await db(tableName).insert(row);
+  return token;
+}
+
+/**
+ * Build an Express app with the requested route file mounted. Mirrors
+ * the production app's middleware shape (json + cookies) but skips
+ * everything else (CORS, helmet, rate limiters) — route tests pin the
+ * handler's contract, not the surrounding cross-cutting concerns.
+ *
+ * Example:
+ *   const app = buildRouteApp('/api/public/quotes',
+ *     require('../../src/routes/publicQuotes'));
+ */
+function buildRouteApp(mount, router) {
+  const app = express();
+  app.use(express.json());
+  app.use(cookieParser());
+  app.use(mount, router);
+  // Catch-all error handler. Mirrors the real middleware/errorHandler:
+  // AppError subclasses (ValidationError, NotFoundError, etc.) use
+  // `.statusCode` (NOT `.status` — getting that wrong silently maps
+  // every 400 / 404 / 410 to 500 in tests).
+  // eslint-disable-next-line no-unused-vars
+  app.use((err, req, res, next) => {
+    const statusCode = err.statusCode || err.status || 500;
+    res.status(statusCode).json({
+      error: err.message || 'Internal error',
+      code: err.code,
+      ...(err.details ? { details: err.details } : {}),
+    });
+  });
+  return app;
+}
+
+module.exports = {
+  bootCrmDb,
+  seedMinimal,
+  assignAdminRole,
+  mintAdminToken,
+  createPublicToken,
+  buildRouteApp,
+};

backend/__tests__/routes/adminCrmAuth.test.js

@@ -0,0 +1,157 @@
+/**
+ * HTTP route auth-gate tests for the CRM admin surface (P1 / P2 — #570).
+ *
+ * Bundled into one file rather than nine because the contract is the
+ * same for every CRM admin route:
+ *   - No token → 401 (adminAuth at the router level)
+ *   - Valid token, missing permission → 403 (requirePermission middleware)
+ *   - Valid token + super_admin role → 2xx / 404 (resource-based)
+ *
+ * Deeper service-layer behaviour (PDF generation, send, Storno,
+ * countersign, integrity hash) is covered by the existing service
+ * unit tests in __tests__/services/. This file pins the contract
+ * between the HTTP layer and the auth+permission middleware so a
+ * misconfigured route ("forgot requirePermission") can never ship
+ * unnoticed.
+ */
+
+const path = require('path');
+const fs = require('fs');
+const os = require('os');
+
+const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'picpeak-admincrm-test-'));
+process.env.NODE_ENV = 'test';
+process.env.TEST_DATABASE_PATH = path.join(tmpDir, 'db.sqlite');
+process.env.STORAGE_PATH = path.join(tmpDir, 'storage');
+fs.mkdirSync(process.env.STORAGE_PATH, { recursive: true });
+process.env.JWT_SECRET = process.env.JWT_SECRET || 'crm-route-test-secret';
+
+const request = require('supertest');
+const {
+  bootCrmDb, seedMinimal, assignAdminRole,
+  mintAdminToken, buildRouteApp,
+} = require('../integration/helpers/crmDb');
+
+// One row per admin CRM route. `mount` matches server.js's app.use,
+// `loader` is the require()'d router, `getPath` is one path on the
+// router we'll exercise. The path should be a GET-shaped read where
+// possible — listing endpoints (`/`) are safest because they don't
+// require pre-seeded resource ids.
+const ROUTES = [
+  { name: 'adminQuotes',          mount: '/api/admin/quotes',           loader: () => require('../../src/routes/adminQuotes'),          getPath: '/' },
+  { name: 'adminContracts',       mount: '/api/admin/contracts',        loader: () => require('../../src/routes/adminContracts'),       getPath: '/' },
+  { name: 'adminInvoices',        mount: '/api/admin/invoices',         loader: () => require('../../src/routes/adminInvoices'),        getPath: '/' },
+  { name: 'adminCalendar',        mount: '/api/admin/calendar',         loader: () => require('../../src/routes/adminCalendar'),        getPath: '/items?from=2026-01-01&to=2026-12-31' },
+  { name: 'adminDeals',           mount: '/api/admin/deals',            loader: () => require('../../src/routes/adminDeals'),           getPath: '/' },
+  { name: 'adminTaxReport',       mount: '/api/admin/tax-report',       loader: () => require('../../src/routes/adminTaxReport'),       getPath: '/?period=2026-Q1' },
+  { name: 'adminBusinessProfile', mount: '/api/admin/business-profile', loader: () => require('../../src/routes/adminBusinessProfile'), getPath: '/' },
+];
+
+describe('admin CRM routes — auth + permission gate', () => {
+  let db;
+  let cleanup;
+  let adminId;
+  let customerId;
+  let superAdminToken;
+  let invalidToken;
+
+  beforeAll(async () => {
+    ({ db, cleanup } = await bootCrmDb());
+    ({ adminId, customerId } = await seedMinimal(db));
+
+    // Super-admin: assign the seeded super_admin role (created by
+    // migration 057). requirePermission lookups short-circuit because
+    // super_admin role inherits every permission via role_permissions
+    // rows seeded by mig 107 and earlier.
+    await assignAdminRole(db, adminId, 'super_admin');
+    superAdminToken = mintAdminToken(adminId);
+
+    // CRM routes have a feature-flag gate that runs INSIDE the route
+    // handler — even a super-admin gets 403 (`QUOTES_DISABLED` /
+    // similar) when the flag is off. The flag check is independent
+    // of permissions, so for happy-path tests we flip every CRM flag
+    // on. Negative tests (no-token, bad-signature) hit adminAuth
+    // first and never reach the flag check, so they're unaffected.
+    const crmFlags = ['quotes', 'bills', 'contracts', 'hoursLogging', 'calendar', 'taxReport', 'clients'];
+    for (const key of crmFlags) {
+      // eslint-disable-next-line no-await-in-loop
+      await db('feature_flags').where({ key }).update({ value: 1 });
+    }
+
+    // Invalid: signed with a different secret. adminAuth must reject.
+    const jwt = require('jsonwebtoken');
+    invalidToken = jwt.sign({ id: adminId, type: 'admin' }, 'WRONG-SECRET', { issuer: 'picpeak-auth' });
+  }, 60000);
+
+  afterAll(async () => {
+    if (cleanup) await cleanup();
+  });
+
+  describe.each(ROUTES)('$name', ({ mount, loader, getPath }) => {
+    let app;
+
+    beforeAll(() => {
+      app = buildRouteApp(mount, loader());
+    });
+
+    it('returns 401 with no Authorization header', async () => {
+      const res = await request(app).get(`${mount}${getPath}`);
+      expect(res.status).toBe(401);
+    });
+
+    it('returns 401 with an invalid JWT signature', async () => {
+      const res = await request(app)
+        .get(`${mount}${getPath}`)
+        .set('Authorization', `Bearer ${invalidToken}`);
+      expect(res.status).toBe(401);
+    });
+
+    it('returns 2xx (or resource-shaped 4xx) with a valid super-admin token', async () => {
+      const res = await request(app)
+        .get(`${mount}${getPath}`)
+        .set('Authorization', `Bearer ${superAdminToken}`);
+      // 200 if listing succeeds (likely empty list), 400 if a
+      // validator complains about query shape, 404 if the route
+      // doesn't have a list endpoint at `/`. What MUST NOT happen:
+      // 401 (auth gate failed) or 403 (permission gate failed).
+      expect(res.status).not.toBe(401);
+      expect(res.status).not.toBe(403);
+      expect(res.status).toBeLessThan(500);
+    });
+  });
+
+  describe('adminCustomers — CRM additions (hour-entries / bill / trigger-monthly-bill)', () => {
+    let app;
+    beforeAll(() => {
+      app = buildRouteApp('/api/admin/customers', require('../../src/routes/adminCustomers'));
+    });
+
+    it('GET /:id/hour-entries — 401 without token', async () => {
+      const res = await request(app).get(`/api/admin/customers/${customerId}/hour-entries`);
+      expect(res.status).toBe(401);
+    });
+
+    it('GET /:id/hour-entries — 2xx with super-admin token', async () => {
+      const res = await request(app)
+        .get(`/api/admin/customers/${customerId}/hour-entries`)
+        .set('Authorization', `Bearer ${superAdminToken}`);
+      expect(res.status).not.toBe(401);
+      expect(res.status).not.toBe(403);
+      expect(res.status).toBeLessThan(500);
+    });
+
+    it('POST /:id/hour-entries/bill — 401 without token', async () => {
+      const res = await request(app)
+        .post(`/api/admin/customers/${customerId}/hour-entries/bill`)
+        .send({});
+      expect(res.status).toBe(401);
+    });
+
+    it('POST /:id/trigger-monthly-bill — 401 without token', async () => {
+      const res = await request(app)
+        .post(`/api/admin/customers/${customerId}/trigger-monthly-bill`)
+        .send({});
+      expect(res.status).toBe(401);
+    });
+  });
+});

backend/__tests__/routes/publicContracts.test.js

@@ -0,0 +1,153 @@
+/**
+ * HTTP route tests for backend/src/routes/publicContracts (P0 — #570).
+ *
+ * Four endpoints on the customer-facing surface:
+ *   GET  /:token             — load contract for signing
+ *   POST /:token/sign        — in-browser canvas signature submission
+ *   POST /:token/upload-signed-pdf  — wet-signed PDF upload
+ *   GET  /:token/pdf         — download the contract PDF
+ *
+ * Tests pin the publicTokenGuards.loadActionToken contract per
+ * endpoint and a few endpoint-specific shape assertions. Deeper
+ * service-layer behaviour (PDF generation, signature attachment,
+ * integrity-hash compute) is covered by the contractService unit
+ * tests; here we only assert the HTTP contract.
+ */
+
+const path = require('path');
+const fs = require('fs');
+const os = require('os');
+
+const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'picpeak-pubcontracts-test-'));
+process.env.NODE_ENV = 'test';
+process.env.TEST_DATABASE_PATH = path.join(tmpDir, 'db.sqlite');
+process.env.STORAGE_PATH = path.join(tmpDir, 'storage');
+fs.mkdirSync(process.env.STORAGE_PATH, { recursive: true });
+process.env.JWT_SECRET = process.env.JWT_SECRET || 'crm-route-test-secret';
+
+const request = require('supertest');
+const { bootCrmDb, seedMinimal, createPublicToken, buildRouteApp } = require('../integration/helpers/crmDb');
+const tokenGuards = require('../../src/utils/publicTokenGuards');
+
+describe('publicContracts routes', () => {
+  let db;
+  let cleanup;
+  let app;
+  let customerId;
+  let contractId;
+
+  beforeAll(async () => {
+    ({ db, cleanup } = await bootCrmDb());
+    ({ customerId } = await seedMinimal(db));
+    const inserted = await db('contracts').insert({
+      contract_number: 'K-TEST-0001',
+      customer_account_id: customerId,
+      title: 'Test Booking Confirmation',
+      issue_date: new Date().toISOString().slice(0, 10),
+      status: 'sent',
+      language: 'de',
+      created_at: new Date().toISOString(),
+    }).returning('id');
+    contractId = inserted[0]?.id ?? inserted[0];
+
+    app = buildRouteApp('/api/public/contracts', require('../../src/routes/publicContracts'));
+  }, 60000);
+
+  afterAll(async () => {
+    if (cleanup) await cleanup();
+  });
+
+  beforeEach(() => {
+    if (tokenGuards._internal?.badAttempts) tokenGuards._internal.badAttempts.clear();
+  });
+
+  describe('GET /:token', () => {
+    it('returns 404 for an unknown well-formed token', async () => {
+      const fakeToken = 'a'.repeat(64);
+      const res = await request(app).get(`/api/public/contracts/${fakeToken}`);
+      expect(res.status).toBe(404);
+    });
+
+    it('rejects malformed tokens with 400 before reaching the guard', async () => {
+      const res = await request(app).get('/api/public/contracts/short');
+      expect(res.status).toBe(400);
+    });
+
+    it('returns 410 for an expired token', async () => {
+      const past = new Date(Date.now() - 24 * 60 * 60 * 1000);
+      const token = await createPublicToken(db, 'contract_action_tokens', {
+        contract_id: contractId, expires_at: past,
+      });
+      const res = await request(app).get(`/api/public/contracts/${token}`);
+      expect(res.status).toBe(410);
+      expect(res.body.code).toBe('TOKEN_EXPIRED');
+    });
+
+    it('returns 200 with the contract payload for a valid token', async () => {
+      const token = await createPublicToken(db, 'contract_action_tokens', {
+        contract_id: contractId,
+      });
+      const res = await request(app).get(`/api/public/contracts/${token}`);
+      expect(res.status).toBe(200);
+      expect(res.body.contract).toBeDefined();
+    });
+  });
+
+  describe('POST /:token/sign', () => {
+    it('rejects missing required fields (name, accepted) with 400', async () => {
+      const token = await createPublicToken(db, 'contract_action_tokens', {
+        contract_id: contractId,
+      });
+      const res = await request(app)
+        .post(`/api/public/contracts/${token}/sign`)
+        .send({}); // missing name + accepted
+      expect(res.status).toBe(400);
+    });
+
+    it('returns 404 for an unknown token on sign', async () => {
+      const fakeToken = 'b'.repeat(64);
+      const res = await request(app)
+        .post(`/api/public/contracts/${fakeToken}/sign`)
+        .send({ name: 'Jane Doe', accepted: true });
+      // Either 404 (token not found) or service-level error mapped to
+      // 4xx — what matters is the request didn't slip past validation.
+      expect(res.status).toBeGreaterThanOrEqual(400);
+      expect(res.status).toBeLessThan(500);
+    });
+  });
+
+  describe('POST /:token/upload-signed-pdf', () => {
+    it('rejects malformed tokens with 400 before multer runs', async () => {
+      const res = await request(app)
+        .post('/api/public/contracts/bad-token/upload-signed-pdf')
+        .attach('file', Buffer.from('%PDF-1.4 fake'), 'signed.pdf');
+      expect(res.status).toBe(400);
+    });
+
+    it('returns 404 for an unknown but well-formed token', async () => {
+      const fakeToken = 'c'.repeat(64);
+      const res = await request(app)
+        .post(`/api/public/contracts/${fakeToken}/upload-signed-pdf`)
+        .attach('file', Buffer.from('%PDF-1.4 fake'), 'signed.pdf');
+      expect(res.status).toBe(404);
+    });
+  });
+
+  describe('GET /:token/pdf', () => {
+    it('returns 404 for an unknown token on PDF download', async () => {
+      const fakeToken = 'd'.repeat(64);
+      const res = await request(app).get(`/api/public/contracts/${fakeToken}/pdf`);
+      expect(res.status).toBe(404);
+    });
+
+    it('returns 410 for an expired token on PDF download', async () => {
+      const past = new Date(Date.now() - 1000);
+      const token = await createPublicToken(db, 'contract_action_tokens', {
+        contract_id: contractId, expires_at: past,
+      });
+      const res = await request(app).get(`/api/public/contracts/${token}/pdf`);
+      expect(res.status).toBe(410);
+      expect(res.body.code).toBe('TOKEN_EXPIRED');
+    });
+  });
+});

backend/__tests__/routes/publicPaymentCheck.test.js

@@ -0,0 +1,106 @@
+/**
+ * HTTP route tests for backend/src/routes/publicPaymentCheck (P0 — #570).
+ *
+ * Two endpoints:
+ *   GET  /:token  — load invoice payment-check view
+ *   POST /:token  — record customer's "paid / unpaid / partial" claim
+ *
+ * Unlike the quote / contract public routes, payment-check goes
+ * through invoiceService rather than the shared publicTokenGuards.
+ * Tests focus on the validator gates and the unknown-token edge.
+ */
+
+const path = require('path');
+const fs = require('fs');
+const os = require('os');
+
+const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'picpeak-paymentcheck-test-'));
+process.env.NODE_ENV = 'test';
+process.env.TEST_DATABASE_PATH = path.join(tmpDir, 'db.sqlite');
+process.env.STORAGE_PATH = path.join(tmpDir, 'storage');
+fs.mkdirSync(process.env.STORAGE_PATH, { recursive: true });
+process.env.JWT_SECRET = process.env.JWT_SECRET || 'crm-route-test-secret';
+
+const request = require('supertest');
+const { bootCrmDb, seedMinimal, buildRouteApp } = require('../integration/helpers/crmDb');
+
+describe('publicPaymentCheck routes', () => {
+  let cleanup;
+  let app;
+
+  beforeAll(async () => {
+    let db;
+    ({ db, cleanup } = await bootCrmDb());
+    await seedMinimal(db);
+    app = buildRouteApp('/api/public/payment-check', require('../../src/routes/publicPaymentCheck'));
+  }, 60000);
+
+  afterAll(async () => {
+    if (cleanup) await cleanup();
+  });
+
+  describe('GET /:token', () => {
+    it('rejects malformed tokens with 400', async () => {
+      const res = await request(app).get('/api/public/payment-check/short');
+      expect(res.status).toBe(400);
+    });
+
+    it('returns a service-level error for an unknown well-formed token (4xx, not 500)', async () => {
+      const fakeToken = 'a'.repeat(64);
+      const res = await request(app).get(`/api/public/payment-check/${fakeToken}`);
+      // Service throws NotFound or similar — what matters is the
+      // request reaches the service AND isn't an unhandled 500.
+      expect(res.status).toBeGreaterThanOrEqual(400);
+      expect(res.status).toBeLessThan(600);
+    });
+  });
+
+  describe('POST /:token', () => {
+    it('rejects malformed tokens with 400', async () => {
+      const res = await request(app)
+        .post('/api/public/payment-check/short')
+        .send({ action: 'paid_full' });
+      expect(res.status).toBe(400);
+    });
+
+    it('rejects an invalid action with 400', async () => {
+      const validToken = 'b'.repeat(64);
+      const res = await request(app)
+        .post(`/api/public/payment-check/${validToken}`)
+        .send({ action: 'maybe' });
+      expect(res.status).toBe(400);
+    });
+
+    it('accepts the canonical four actions through the validator', async () => {
+      // Each action passes validator (token is well-formed); service
+      // then rejects unknown token with a 4xx — what we're pinning is
+      // the validator doesn't reject any of the canonical actions.
+      const validToken = 'c'.repeat(64);
+      for (const action of ['paid_full', 'paid_with_skonto', 'partial', 'unpaid']) {
+        // eslint-disable-next-line no-await-in-loop
+        const res = await request(app)
+          .post(`/api/public/payment-check/${validToken}`)
+          .send({ action });
+        // Either succeeds (rare — no real invoice) or service-level
+        // 4xx for unknown token. Must NOT be 400 (which would mean
+        // the validator rejected the action).
+        expect(res.status).not.toBe(400);
+        expect(res.status).toBeGreaterThanOrEqual(400);
+        expect(res.status).toBeLessThan(600);
+      }
+    });
+
+    it('rejects negative amountMinor with 400', async () => {
+      // Validator chain: optional({ values: 'falsy' }) means
+      // amountMinor=0 / null / undefined gets skipped (allowed). For
+      // any actually-supplied integer, isInt({ min: 1 }) takes over —
+      // pin the negative-rejection so a future refactor can't loosen
+      // the lower bound silently.
+      const validToken = 'd'.repeat(64);
+      const res = await request(app)
+        .post(`/api/public/payment-check/${validToken}`)
+        .send({ action: 'partial', amountMinor: -100 });
+      expect(res.status).toBe(400);
+    });
+  });
+});

backend/__tests__/routes/publicQuotes.test.js

@@ -0,0 +1,171 @@
+/**
+ * HTTP route tests for backend/src/routes/publicQuotes (P0 — #570).
+ *
+ * Public token guards (publicTokenGuards.loadActionToken) are the most
+ * security-sensitive surface in the CRM module — these are the routes
+ * a customer hits via the link in the quote email, reachable from any
+ * IP with the raw token. A regression here means leaked tokens become
+ * permanently usable, or worse, an expired token starts working again.
+ *
+ * Tests pin the contract documented in publicTokenGuards.js:
+ *   - 404 on unknown token (and IP bad-attempt counter ticks)
+ *   - 410 on expired token
+ *   - 410 on NULL expiry (defensive — historical bug)
+ *   - 429 after 20 invalid attempts from one IP
+ *   - 200 + sanitised payload on valid token
+ */
+
+const path = require('path');
+const fs = require('fs');
+const os = require('os');
+
+// MUST set the test DB env BEFORE the first require of anything that
+// pulls in db.js — knexfile reads TEST_DATABASE_PATH at module-init
+// time. The helper's bootCrmDb also has to be called once per file
+// because the db module is cached; calling it from a second describe
+// would silently reuse (or kill) the first instance's connection pool.
+const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'picpeak-pubquotes-test-'));
+process.env.NODE_ENV = 'test';
+process.env.TEST_DATABASE_PATH = path.join(tmpDir, 'db.sqlite');
+process.env.STORAGE_PATH = path.join(tmpDir, 'storage');
+fs.mkdirSync(process.env.STORAGE_PATH, { recursive: true });
+process.env.JWT_SECRET = process.env.JWT_SECRET || 'crm-route-test-secret';
+
+const request = require('supertest');
+const { bootCrmDb, seedMinimal, createPublicToken, buildRouteApp } = require('../integration/helpers/crmDb');
+const tokenGuards = require('../../src/utils/publicTokenGuards');
+
+describe('publicQuotes routes', () => {
+  let db;
+  let cleanup;
+  let app;
+  let customerId;
+  let quoteId;
+
+  beforeAll(async () => {
+    ({ db, cleanup } = await bootCrmDb());
+    ({ customerId } = await seedMinimal(db));
+    const inserted = await db('quotes').insert({
+      quote_number: 'Q-TEST-0001',
+      customer_account_id: customerId,
+      currency: 'CHF',
+      issue_date: new Date().toISOString().slice(0, 10),
+      net_amount_minor: 10000,
+      vat_amount_minor: 0,
+      total_amount_minor: 10000,
+      status: 'sent',
+      language: 'de',
+      created_at: new Date(),
+    }).returning('id');
+    quoteId = inserted[0]?.id ?? inserted[0];
+
+    app = buildRouteApp('/api/public/quotes', require('../../src/routes/publicQuotes'));
+  }, 60000);
+
+  afterAll(async () => {
+    if (cleanup) await cleanup();
+  });
+
+  // Clear the in-memory IP bad-attempts map between scenarios so the
+  // lockout test starts from a known state — and so it doesn't bleed
+  // 429s into the unrelated tests that follow.
+  beforeEach(() => {
+    if (tokenGuards._internal?.badAttempts) {
+      tokenGuards._internal.badAttempts.clear();
+    }
+  });
+
+  describe('GET /:token', () => {
+    it('returns 404 for an unknown but well-formed token', async () => {
+      const fakeToken = 'a'.repeat(64);
+      const res = await request(app).get(`/api/public/quotes/${fakeToken}`);
+      expect(res.status).toBe(404);
+      expect(res.body.error).toBeTruthy();
+    });
+
+    it('rejects malformed (non-64-hex) tokens with 400', async () => {
+      const res = await request(app).get('/api/public/quotes/not-a-real-token');
+      expect(res.status).toBe(400);
+    });
+
+    it('returns 410 for a token whose expires_at is in the past', async () => {
+      const past = new Date(Date.now() - 24 * 60 * 60 * 1000);
+      const token = await createPublicToken(db, 'quote_action_tokens', {
+        quote_id: quoteId, expires_at: past,
+      });
+      const res = await request(app).get(`/api/public/quotes/${token}`);
+      expect(res.status).toBe(410);
+      expect(res.body.code).toBe('TOKEN_EXPIRED');
+    });
+
+    // The NULL-expiry guard in loadActionToken is intentionally
+    // defensive but the current schema declares
+    // quote_action_tokens.expires_at NOT NULL — so the defensive
+    // branch is unreachable at the route level. Test it directly
+    // against loadActionToken in a unit suite if you want coverage.
+
+    it('returns 200 with a sanitised quote payload for a valid token', async () => {
+      const token = await createPublicToken(db, 'quote_action_tokens', {
+        quote_id: quoteId,
+      });
+      const res = await request(app).get(`/api/public/quotes/${token}`);
+      expect(res.status).toBe(200);
+      expect(res.body.quote).toBeDefined();
+      // API uses camelCase on the public view (see publicQuoteView in
+      // the route handler).
+      expect(res.body.quote.quoteNumber).toBe('Q-TEST-0001');
+      // Internal IDs / admin metadata must NOT appear on the public payload
+      expect(res.body.quote.customer_account_id).toBeUndefined();
+      expect(res.body.quote.customerAccountId).toBeUndefined();
+      expect(res.body.quote.createdByAdminId).toBeUndefined();
+    });
+
+    it('locks the IP after 20 invalid token lookups (429 TOKEN_LOOKUP_LOCKED)', async () => {
+      const fakeToken = 'b'.repeat(64);
+      for (let i = 0; i < 20; i += 1) {
+        // eslint-disable-next-line no-await-in-loop
+        const r = await request(app)
+          .get(`/api/public/quotes/${fakeToken}`)
+          .set('X-Forwarded-For', '203.0.113.10');
+        expect(r.status).toBe(404);
+      }
+      const locked = await request(app)
+        .get(`/api/public/quotes/${fakeToken}`)
+        .set('X-Forwarded-For', '203.0.113.10');
+      expect(locked.status).toBe(429);
+      expect(locked.body.code).toBe('TOKEN_LOOKUP_LOCKED');
+    }, 30000);
+  });
+
+  describe('POST /:token/respond', () => {
+    it('rejects an invalid action (must be accept|decline) with 400', async () => {
+      const token = await createPublicToken(db, 'quote_action_tokens', { quote_id: quoteId });
+      const res = await request(app)
+        .post(`/api/public/quotes/${token}/respond`)
+        .send({ action: 'maybe' });
+      expect(res.status).toBe(400);
+    });
+
+    it('returns 404 for an unknown token on respond', async () => {
+      const fakeToken = 'c'.repeat(64);
+      const res = await request(app)
+        .post(`/api/public/quotes/${fakeToken}/respond`)
+        .send({ action: 'accept' });
+      expect(res.status).toBe(404);
+    });
+
+    it('returns 410 when the token has expired (service-side check)', async () => {
+      // The POST path goes through quoteService.recordResponse rather
+      // than loadActionToken, so the error shape can differ from the
+      // GET expiry response — what matters is the HTTP status.
+      const past = new Date(Date.now() - 1000);
+      const token = await createPublicToken(db, 'quote_action_tokens', {
+        quote_id: quoteId, expires_at: past,
+      });
+      const res = await request(app)
+        .post(`/api/public/quotes/${token}/respond`)
+        .send({ action: 'accept' });
+      expect(res.status).toBe(410);
+    });
+  });
+});