Add PostgreSQL-backed background worker

apps/web/README.md

@@ -145,15 +145,14 @@ App listens on `${WEB_PORT:-${PORT:-3000}}` on the host (container port is alway
 
 ### Scheduled recurring invoices
 
-The app container does not run a cron daemon. It starts the web server with
-`bun migrate.ts && bun run start`, and recurring invoice generation only happens
-when something calls `POST /api/cron/generate-recurring` with
-`Authorization: Bearer $CRON_SECRET`.
+The Compose stack includes a dedicated PostgreSQL-backed worker. It discovers due
+recurring invoices every minute, enqueues idempotent jobs, and processes them with
+bounded retries and stale-lock recovery. No Coolify scheduled task or Redis
+service is required.
 
-- **Coolify deploys:** use a Coolify scheduled task to call the endpoint.
-- **Full Docker deploys:** use host cron, a small scheduler sidecar, or an
-  external scheduler to call
-  `http://localhost:${WEB_PORT:-${PORT:-3000}}/api/cron/generate-recurring`.
+`POST /api/cron/generate-recurring` remains available as an optional authenticated
+"schedule now" hook. It only enqueues due work; invoice generation stays in the
+worker.
 
 ### 3. Updating an existing deploy
 
@@ -170,7 +169,7 @@ git pull
 | `../../scripts/docker-deploy.sh` or root `docker compose up -d --build` | Yes | Yes — on app container start |
 | `docker compose restart app` | No | Yes — migrate runs again (no-op if up to date) |
 
-Prune old app images occasionally: `docker image prune -f` (or remove specific `beenvoice:*` tags).
+Prune old app and worker images occasionally: `docker image prune -f` (or remove specific `beenvoice:*` / `beenvoice-worker:*` tags).
 
 To verify migration files match the journal before deploy: `bun run db:verify-journal`.