Run background jobs on a pg-boss queue; add e2e tests, CI and deploy script

Timed jobs move from in-process timers to a job registry run by pg-boss:
once per schedule across processes, retries, run history, cron schedules
in the church timezone, and an admin Background jobs page with Run now.
Playwright end-to-end tests run against their own seeded database. A
Gitea Actions workflow runs backend tests, frontend checks and the e2e
tests, and deploys v* tags with scripts/deploy.sh once secrets are set.
Also fixes the at-the-door check-in count for multi-day tickets.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -81,8 +81,26 @@ Documentation: see Frontend README for environment and scripts.
   - npm run dev
   - Next.js dev server runs at http://localhost:3000 by default; if it conflicts with backend, it will pick another port (e.g., 3001). Ensure NEXT_PUBLIC_API_URL points to the backend port.
 
+## Tests
+
+- Backend unit tests: `cd backend && npm test`
+- End-to-end tests (Playwright), from the repo root:
+  - once: `npm install` and `npx playwright install chromium`
+  - `npm run test:e2e`
+  - They start their own backend (port 5100) and frontend (port 3100) against a separate
+    database — `backend/.env`'s `DATABASE_URL` with `_e2e` added to the name, or
+    `E2E_DATABASE_URL` — which is dropped, recreated and seeded on every run. Your own dev
+    servers and database aren't touched. The database user needs permission to create
+    databases.
+- CI: `.gitea/workflows/ci.yml` runs all of the above on every push once a Gitea Actions
+  runner is registered. Pushing a `v*` tag also deploys with `scripts/deploy.sh` when the
+  `DEPLOY_HOST`, `DEPLOY_USER`, `DEPLOY_SSH_KEY` (and optional `DEPLOY_PATH`) secrets are set.
+
 ## Deployment
 
+To update a running install to a release: `bash scripts/deploy.sh v1.34.0` on the server
+(backs up the database, migrates, builds, reloads PM2).
+
 ### Backend Deployment
 
 1. Provision a PostgreSQL database and set DATABASE_URL.