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>

.env.example

@@ -0,0 +1,47 @@
+# 数据库
+DATABASE_URL=postgresql+asyncpg://rss:rss@postgres:5432/rss_platform
+
+# Redis
+REDIS_URL=redis://redis:6379/0
+
+# JWT
+# 生产环境必须使用随机生成的、长度 >= 32 的字符串
+SECRET_KEY=change-me-in-production-min-32-chars-long-required
+ACCESS_TOKEN_EXPIRE_MINUTES=15
+REFRESH_TOKEN_EXPIRE_DAYS=7
+
+# AI（占位，后续阶段启用）
+AI_DEFAULT_PROVIDER=openai
+AI_DEFAULT_MODEL=gpt-4o-mini
+
+# 对象存储
+STORAGE_TYPE=minio
+MINIO_ENDPOINT=minio:9000
+MINIO_ACCESS_KEY=minioadmin
+MINIO_SECRET_KEY=minioadmin
+MINIO_BUCKET=rss-platform
+
+# CORS
+CORS_ALLOWED_ORIGINS=http://localhost:5173,http://127.0.0.1:5173
+
+# 敏感设置加密密钥（可选但强烈建议）
+# 生成方式：python -c "from cryptography.fernet import Fernet; print(Fernet.generate_key().decode())"
+# 为空时敏感配置以明文存储
+SETTINGS_ENCRYPTION_KEY=
+
+# 日志
+LOG_LEVEL=INFO
+
+# RSS 抓取
+FETCH_CONCURRENCY=10
+FETCH_TIMEOUT=30
+DEFAULT_FETCH_INTERVAL=60
+MIN_FETCH_INTERVAL=15
+
+# 端口（开发环境）
+BACKEND_PORT=8000
+FRONTEND_PORT=5173
+POSTGRES_PORT=5432
+REDIS_PORT=6379
+MINIO_API_PORT=9000
+MINIO_CONSOLE_PORT=9001