feat(deploy): docker image, caddy, compose, e2e script

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MMHQTtnQtQqL8muAXHr9kd

.env.example

@@ -0,0 +1,11 @@
+POSTGRES_PASSWORD=change-me
+AUTH_USER=admin
+AUTH_PASS=change-me
+# 32 bytes base64-encoded: openssl rand -base64 32
+ENC_KEY=
+SESSION_SECRET=change-me-long-random
+WORKER_CONCURRENCY=4
+HTTP_PORT=80
+# For HTTPS + Let's Encrypt (docker-compose.tls.yml override): set a real domain and email
+DOMAIN=
+ACME_EMAIL=