feat(workflows): implement remaining stub actions (prepare_quote, prepare_gallery, reserve_date)

These were the last guard-stubbed actions — offered in the builder palette but
refused on enable. Now all three are real, backed by existing converters:

- prepare_gallery: alias of prepare_event (a gallery IS an event in picpeak).
- reserve_date: convertToEvent({ skipInvoices: true }) — a pure draft date hold
  with no money documents (new skipInvoices option on convertToEvent).
- prepare_quote: createQuote (customer entity) or duplicateQuote (quote entity),
  producing a status='draft' quote; idempotent via ctx.vars.preparedQuoteId.

With no stubs left, the enable-guard switches from a hardcoded DOCUMENT_ACTIONS
list to a registry lookup: an action node whose config.action has no registered
handler is unimplementable. This can't drift from what the engine can run and
also catches typo'd/future actions. (Fixes the enable-route node mapping to
carry node.type so the action-node filter matches.)

Extends the single-connection SQLite in-trx deadlock fixes to the quote-create
path (prepare_quote runs unattended): nextQuoteNumber reads getAppSetting
through trx, createQuote logs via trx and hoists its hasColumnCached schema-drift
checks before the transaction.

Adds tests for reserve_date (no invoices), prepare_quote (draft, no deadlock),
and registry coverage; retargets the enable-guard refusal test at a genuinely
unregistered action. Full backend suite: 985 passed, 1 skipped.

backend/__tests__/integration/bookingCutover.test.js

@@ -76,6 +76,31 @@ describe('booking cutover — draft invoices on hold', () => {
     expect(q.converted_event_id).toBe(res.eventId);
   });
 
+  it('reserve_date path (convertToEvent skipInvoices) creates a draft event with NO invoices', async () => {
+    const quoteId = await acceptedQuote();
+    const res = await quoteService.convertToEvent(quoteId, adminId, { hold: true, skipInvoices: true });
+    expect(res.eventId).toBeGreaterThanOrEqual(1);
+    expect(res.invoiceIds).toEqual([]);
+    const invCount = await db('invoices').where({ event_id: res.eventId }).count({ c: '*' }).first();
+    expect(Number(invCount.c)).toBe(0); // pure date hold — no money documents
+  });
+
+  it('prepare_quote path (duplicateQuote) creates a new DRAFT quote — no in-trx deadlock', async () => {
+    const quoteId = await acceptedQuote();
+    const newId = await quoteService.duplicateQuote(quoteId, adminId);
+    expect(newId).toBeGreaterThanOrEqual(1);
+    expect(newId).not.toBe(quoteId);
+    const q = await db('quotes').where({ id: newId }).first();
+    expect(q.status).toBe('draft');
+  });
+
+  it('registers prepare_gallery / reserve_date / prepare_quote as real actions', () => {
+    const { registry } = require('../../src/services/workflows'); // loads actions.js (side-effect registration)
+    for (const a of ['prepare_gallery', 'reserve_date', 'prepare_quote', 'prepare_event', 'prepare_invoice', 'send_document']) {
+      expect(typeof registry.getAction(a)).toBe('function');
+    }
+  });
+
   it('prepare_contract path (createFromQuote) completes under SQLite — no in-trx deadlock', async () => {
     const contractService = require('../../src/services/contractService');
     const quoteId = await acceptedQuote();