feat(deploy): CI/CD Gitea Actions + stack Docker prod pour xip.kerboul.me

- docker-compose.prod.yml: postgres + redis + backend (bun) + web (nginx single-origin)
- backend/Dockerfile + entrypoint: prisma migrate deploy + seed idempotent au boot
- frontend/Dockerfile: build Vite (VITE_API_URL=https://xip.kerboul.me) servi par nginx
- deploy/nginx.conf: proxy /api + /ws vers le backend, SPA fallback
- .gitea/workflows/deploy.yml: auto-deploy SSH sur push main (runner CT121 -> CT502)
- scripts/deploy.sh: pull + rebuild de la stack
- mode open-bar (XIP_OPEN_BAR): paywall off pour tous en prod, via isFree() centralise

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docker-compose.prod.yml

@@ -0,0 +1,67 @@
+# Production stack for XIP — runs on the dedicated CT (xip-app, Echelon CT502).
+# Postgres + Redis + bun backend + nginx (serves SPA, proxies /api and /ws).
+# Secrets come from .env.prod (gitignored), loaded via `--env-file .env.prod`.
+services:
+  postgres:
+    image: postgres:16
+    restart: unless-stopped
+    environment:
+      POSTGRES_DB: ${POSTGRES_DB:-xip}
+      POSTGRES_USER: ${POSTGRES_USER:-xip}
+      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:?POSTGRES_PASSWORD must be set in .env.prod}
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U ${POSTGRES_USER:-xip}"]
+      interval: 5s
+      timeout: 5s
+      retries: 20
+
+  redis:
+    image: redis:7
+    restart: unless-stopped
+    command: ["redis-server", "--appendonly", "yes"]
+    volumes:
+      - redis_data:/data
+    healthcheck:
+      test: ["CMD", "redis-cli", "ping"]
+      interval: 5s
+      timeout: 5s
+      retries: 20
+
+  backend:
+    build:
+      context: .
+      dockerfile: backend/Dockerfile
+    restart: unless-stopped
+    environment:
+      DATABASE_URL: postgresql://${POSTGRES_USER:-xip}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB:-xip}
+      REDIS_URL: redis://redis:6379
+      PORT: "3000"
+      NODE_ENV: production
+      # Prod "open bar": paywall disabled for everyone (see backend/src/lib/ip.ts).
+      XIP_OPEN_BAR: ${XIP_OPEN_BAR:-true}
+    volumes:
+      - uploads_data:/app/uploads
+    depends_on:
+      postgres:
+        condition: service_healthy
+      redis:
+        condition: service_healthy
+
+  web:
+    build:
+      context: .
+      dockerfile: frontend/Dockerfile
+      args:
+        VITE_API_URL: ${PUBLIC_URL:-https://xip.kerboul.me}
+    restart: unless-stopped
+    ports:
+      - "80:80"
+    depends_on:
+      - backend
+
+volumes:
+  postgres_data:
+  redis_data:
+  uploads_data: