refactor: remove storage, backup, plugin/marketplace features

- Delete app/storage/ (blob_store, vector_store, encryption)
- Delete app/marketplace/ (plugin_registry, plugin_review, revenue_share)
- Delete routes: backup.py, plugins.py, storage.py, vectors.py
- Relocate embed endpoint to POST /chat/embed
- Rewrite migration 001 (remove storage/plugin tables)
- Delete migration 002 (seed_plugins)
- Remove S3/Pinecone/Qdrant env vars from settings
- Remove storage/backup quotas from tier_manager
- Remove MinIO and Qdrant from docker-compose
- Delete tests: test_backup, test_plugins, test_storage
- Update README.md and clean .env.example

docker-compose.yml

@@ -36,37 +36,6 @@ services:
   #   image: redis:7-alpine
   #   restart: unless-stopped
 
-  # ── Local S3-compatible storage (MinIO) ──
-  minio:
-    image: minio/minio:latest
-    command: server /data --console-address ":9001"
-    ports:
-      - "9000:9000"
-      - "9001:9001"
-    environment:
-      MINIO_ROOT_USER: minioadmin
-      MINIO_ROOT_PASSWORD: minioadmin
-    volumes:
-      - minio_data:/data
-    healthcheck:
-      test: ["CMD", "mc", "ready", "local"]
-      interval: 5s
-      timeout: 5s
-      retries: 5
-    restart: unless-stopped
-
-  # ── Local vector store (Qdrant) ──
-  qdrant:
-    image: qdrant/qdrant:latest
-    ports:
-      - "6333:6333"
-      - "6334:6334"
-    volumes:
-      - qdrant_data:/qdrant/storage
-    restart: unless-stopped
-
 volumes:
   postgres_data:
-  minio_data:
-  qdrant_data:
   copilot_tokens: