Enhance Docker deployment: structured logging, health checks, resource limits, entrypoint script

- Add structured logging config with JSON/text format support
- Create docker-entrypoint.sh with dependency health checks
- Enhance /health endpoint with DB and Redis connectivity checks
- Add resource limits (CPU/memory) for all services
- Add network aliases for service discovery
- Add container hostnames for better identification
- Reduce health check timeout from 20s to 5s
- Add build metadata labels to Dockerfile
- Use ENTRYPOINT for dependency checking before app startup
- Log rotation: 50m per file, 5 files max

backend/scripts/docker-entrypoint.sh

@@ -0,0 +1,57 @@
+#!/usr/bin/env bash
+set -e
+
+echo "============================================"
+echo "  MTG Online Backend - Starting"
+echo "  $(date -u '+%Y-%m-%d %H:%M:%S UTC')"
+echo "============================================"
+
+# Wait for PostgreSQL to be ready
+echo "[entrypoint] Waiting for PostgreSQL databases..."
+for db in mtgo_platform mtgdata mtgo_mirror; do
+    host="postgres_${db}"
+    echo "  Checking ${host}..."
+    until python -c "
+import asyncio, asyncpg
+async def check():
+    try:
+        conn = await asyncpg.connect(host='${host}', port=5432, user='postgres', password='postgres', database='${db}')
+        await conn.close()
+        return True
+    except Exception:
+        return False
+asyncio.run(check())
+" 2>/dev/null; do
+        echo "    ${host} not ready, waiting 2s..."
+        sleep 2
+    done
+    echo "  ${host} is ready!"
+done
+
+# Wait for Redis to be ready
+echo "[entrypoint] Waiting for Redis..."
+until python -c "
+import asyncio, redis.asyncio as aioredis
+async def check():
+    try:
+        r = aioredis.from_url('redis://redis:6379/0')
+        await r.ping()
+        await r.close()
+        return True
+    except Exception:
+        return False
+asyncio.run(check())
+" 2>/dev/null; do
+    echo "  Redis not ready, waiting 2s..."
+    sleep 2
+done
+echo "  Redis is ready!"
+
+# Run database migrations
+echo "[entrypoint] Running Alembic migrations..."
+python -m alembic upgrade head
+echo "[entrypoint] Migrations complete."
+
+# Start the application
+echo "[entrypoint] Starting uvicorn..."
+exec python -m uvicorn app.main:app --host 0.0.0.0 --port 8000 --forwarded-allow-ips '*' --log-level info