test: prove module database access with PostgreSQL

Add a real installed-module fixture (core/tests/fixtures/module-database-integration/db-facade)
with its own manifest, Drizzle schema, drizzle-kit-generated migration, and permissioned HTTP
routes, then exercise it end to end in a new apps/api PostgreSQL integration suite: explicit
migration application before the module runtime starts (never auto-created), start/stop/HTTP
handlers sharing one ModuleDatabase facade by reference, authorized read/mutation/transaction
commit and rollback against real PostgreSQL, denied/rejected-origin/OPTIONS/HEAD requests never
reaching the module or its table, and both a module-caught and an uncaught real database failure
sanitizing exactly as pass 1 established. Registered alongside the existing suites in
vitest.migrations.integration.config.ts; no production code, schema, or migration changed.

core/tests/fixtures/module-database-integration/db-facade/package.json

@@ -0,0 +1,9 @@
+{
+  "name": "@test/module-db-facade",
+  "version": "0.1.0",
+  "type": "module",
+  "private": true,
+  "ekklesia": {
+    "layer": "module"
+  }
+}