Initial commit: RSS platform phase 1 skeleton with code review fixes

Features:
- FastAPI + SQLAlchemy 2.0 async + PostgreSQL/pgvector + Redis backend
- Vue 3 + TypeScript + Element Plus frontend
- JWT auth with access/refresh tokens and revocation
- Admin/member RBAC
- RSS feed CRUD and article listing
- Settings management with Fernet encryption for sensitive values
- Redis distributed lock service
- Alembic initial migration
- Docker Compose development environment

Fixes from code review:
- Fix DB session leak in dependency injection
- Restrict registration to admin only
- Add default admin password warning
- Implement JWT refresh tokens and jti blacklist
- Strengthen password policy
- Use func.count for pagination totals
- Replace NullPool with AsyncAdaptedQueuePool
- Remove init_db from lifespan to enforce alembic migrations
- Add request_id middleware and logging filter
- Fix vite.config.ts env loading
- Add frontend token refresh interceptor
- Add Vue error handler

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

backend/app/core/redis.py

@@ -0,0 +1,32 @@
+"""Redis connection management."""
+from redis.asyncio import Redis
+
+from app.core.config import settings
+
+_redis: Redis | None = None
+
+
+async def get_redis() -> Redis:
+    """Get or create Redis connection."""
+    global _redis
+    if _redis is None:
+        _redis = Redis.from_url(settings.REDIS_URL, decode_responses=True)
+    return _redis
+
+
+async def close_redis() -> None:
+    """Close Redis connection."""
+    global _redis
+    if _redis:
+        await _redis.close()
+        _redis = None
+
+
+async def check_redis_health() -> bool:
+    """Check if Redis is reachable."""
+    try:
+        redis = await get_redis()
+        await redis.ping()
+        return True
+    except Exception:
+        return False