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/tests/conftest.py

@@ -0,0 +1,33 @@
+"""Test configuration."""
+import pytest
+from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
+from sqlalchemy.orm import sessionmaker
+
+from app.models.base import Base
+
+
+@pytest.fixture(scope="function")
+async def db():
+    """Create a fresh in-memory SQLite database for each test."""
+    engine = create_async_engine(
+        "sqlite+aiosqlite:///:memory:",
+        future=True,
+        echo=False,
+    )
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+
+    AsyncSessionLocal = sessionmaker(
+        engine,
+        class_=AsyncSession,
+        expire_on_commit=False,
+        autoflush=False,
+        autocommit=False,
+    )
+
+    async with AsyncSessionLocal() as session:
+        yield session
+
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.drop_all)
+    await engine.dispose()