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>

plugins/deduplication/current.py

@@ -0,0 +1,34 @@
+"""Default deduplication plugin placeholder."""
+from dataclasses import dataclass
+from typing import Dict, List
+
+
+@dataclass
+class DedupInput:
+    article_id: str
+    title: str
+    link: str
+    content: str
+    content_length: int
+    published_at: str
+    feed_id: str
+
+
+@dataclass
+class DuplicateGroup:
+    representative_id: str
+    member_ids: List[str]
+    reason: str
+    similarity_scores: Dict[str, float]
+
+
+class DeduplicationPlugin:
+    """Default deduplication plugin."""
+
+    name = "default_placeholder"
+    version = "0.1.0"
+
+    def find_duplicates(self, articles: List[DedupInput]) -> List[DuplicateGroup]:
+        """Find duplicate articles."""
+        # Placeholder implementation
+        return []