fix(event-types): un-hardcode event type dependencies in v1 API and CRM (#800)

Split out of #801 so the public-API behavior change gets its own review:

- v1 POST /events validates event_type against the live event_types
  catalog instead of the hardcoded whitelist — custom types created in
  Settings → Event Types were rejected with 400. BREAKING for the
  never-seeded 'family' slug, which the old whitelist silently accepted
  and wrote as a dangling reference; create a matching event type to
  keep using it
- new GET /api/v1/event-types (read scope) so API-token clients can
  discover valid slugs; OpenAPI enum replaced accordingly
- standalone contract→event conversion no longer hardcodes
  event_type: 'wedding' — it resolves via crm_default_event_type, then
  the catalog catch-all, same chain as quote→event conversion
- resolveDefaultEventType moved from quoteService to eventTypeService
  for shared use (no behavior change)

backend/__tests__/integration/eventTypeDefaults.test.js

@@ -0,0 +1,50 @@
+/**
+ * Catalog-driven event-type defaults (#800 follow-up).
+ *
+ * The contract→event conversion used to hardcode `event_type: 'wedding'` and
+ * the v1 API validated against a fixed whitelist. Both now follow the live
+ * event_types catalog; these tests pin the shared resolver.
+ */
+
+const { bootCrmDb } = require('./helpers/crmDb');
+
+describe('resolveDefaultEventType follows the catalog', () => {
+  let db;
+  let cleanup;
+  let eventTypeService;
+
+  beforeAll(async () => {
+    ({ db, cleanup } = await bootCrmDb());
+    // Require AFTER bootCrmDb so the service shares this db instance
+    // (see crmDb.js — a second knex pool on one SQLite file deadlocks).
+    eventTypeService = require('../../src/services/eventTypeService');
+  }, 120000);
+
+  afterAll(async () => {
+    if (cleanup) await cleanup();
+  });
+
+  it("prefers the 'other' catch-all while it is active", async () => {
+    expect(await eventTypeService.resolveDefaultEventType()).toBe('other');
+  });
+
+  it('falls over to the first active type when other is deactivated', async () => {
+    const other = await db('event_types').where({ slug_prefix: 'other' }).first();
+    await db('event_types').where({ id: other.id }).update({ is_active: 0 });
+
+    const resolved = await eventTypeService.resolveDefaultEventType();
+    expect(resolved).not.toBe('other');
+    expect(await db('event_types').where({ slug_prefix: resolved }).first()).toBeTruthy();
+
+    await db('event_types').where({ id: other.id }).update({ is_active: 1 });
+  });
+
+  it("returns the literal 'other' only for an empty catalog", async () => {
+    const rows = await db('event_types').select('*');
+    await db('event_types').del();
+
+    expect(await eventTypeService.resolveDefaultEventType()).toBe('other');
+
+    await db('event_types').insert(rows);
+  });
+});