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/schemas/common.py

@@ -0,0 +1,28 @@
+"""Common Pydantic schemas."""
+from pydantic import BaseModel, ConfigDict, Field
+
+
+class PaginationParams(BaseModel):
+    """Pagination query parameters."""
+
+    skip: int = Field(default=0, ge=0)
+    limit: int = Field(default=50, ge=1, le=200)
+
+
+class PaginatedResponse(BaseModel):
+    """Paginated response wrapper."""
+
+    total: int
+    items: list
+
+
+class MessageResponse(BaseModel):
+    """Simple message response."""
+
+    message: str
+
+
+class BaseSchema(BaseModel):
+    """Base schema with ORM mode."""
+
+    model_config = ConfigDict(from_attributes=True)