feat: implement vector sync scanner and processor (ADR-007 Phase 2)

Implements background vector database synchronization using anyio
TaskGroups for BasicAuth mode with single-user credentials.

Scanner Implementation:
- Periodic document discovery (hourly, configurable)
- Timestamp-based change detection (Nextcloud vs Qdrant)
- Wake event for immediate scanning on-demand
- Supports both initial sync (all docs) and incremental sync (changes only)
- Detects deleted documents and queues for removal

Processor Implementation:
- Concurrent document processing pool (3 workers default)
- I/O-bound embedding generation via Ollama API
- Retry logic with exponential backoff (3 retries)
- Document chunking (512 words, 50-word overlap)
- Handles both index and delete operations
- Upserts vectors to Qdrant with rich metadata

App Lifespan Integration:
- Extended AppContext with background task state
- Modified app_lifespan_basic() to start tasks via anyio TaskGroups
- Graceful shutdown with coordinated task cancellation
- Only activates when VECTOR_SYNC_ENABLED=true

Embedding Service:
- OllamaEmbeddingProvider with TLS support
- Singleton pattern for shared client instances
- Batch embedding support for efficiency
- Auto-detects embedding dimension (768 for nomic-embed-text)

Qdrant Client:
- Async client wrapper with singleton pattern
- Auto-creates collection on first use
- COSINE distance metric for semantic similarity
- Integrates with embedding service for dimension detection

Health Check Enhancement:
- Added Qdrant status check to /health/ready endpoint
- Only checks when VECTOR_SYNC_ENABLED=true
- 2-second timeout for health probe
- Reports connection errors with details

Configuration:
- VECTOR_SYNC_ENABLED: Enable background sync
- VECTOR_SYNC_SCAN_INTERVAL: Scanner frequency (3600s default)
- VECTOR_SYNC_PROCESSOR_WORKERS: Concurrent processors (3 default)
- QDRANT_URL, QDRANT_API_KEY, QDRANT_COLLECTION: Vector DB config
- OLLAMA_BASE_URL, OLLAMA_EMBEDDING_MODEL: Embedding service config

Dependencies Added:
- qdrant-client>=1.7.0: Vector database client

Docker Compose:
- Added Qdrant service with health check
- Exposed ports 6333 (REST) and 6334 (gRPC)
- Configured MCP service with vector sync environment
- Added qdrant-data volume for persistence

Known Issue:
- FastMCP lifespan not triggering for streamable-http transport
- Background tasks will start once lifespan integration is complete
- Lifespan triggers on MCP session establishment, not server startup

Related: ADR-007 Background Vector Database Synchronization

🤖 Generated with Claude Code (https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

docker-compose.yml

@@ -74,6 +74,8 @@ services:
     depends_on:
       app:
         condition: service_healthy
+      qdrant:
+        condition: service_healthy
     ports:
       - 127.0.0.1:8000:8000
     environment:
@@ -81,6 +83,21 @@ services:
       - NEXTCLOUD_USERNAME=admin
       - NEXTCLOUD_PASSWORD=admin
 
+      # Vector sync configuration (ADR-007)
+      - VECTOR_SYNC_ENABLED=true
+      - VECTOR_SYNC_SCAN_INTERVAL=3600
+      - VECTOR_SYNC_PROCESSOR_WORKERS=3
+
+      # Qdrant configuration
+      - QDRANT_URL=http://qdrant:6333
+      - QDRANT_API_KEY=${QDRANT_API_KEY:-my_secret_api_key}
+      - QDRANT_COLLECTION=nextcloud_content
+
+      # Ollama configuration
+      - OLLAMA_BASE_URL=https://ollama.internal.coutinho.io:443
+      - OLLAMA_EMBEDDING_MODEL=nomic-embed-text
+      - OLLAMA_VERIFY_SSL=true
+
   mcp-oauth:
     build: .
     command: ["--transport", "streamable-http", "--oauth", "--port", "8001", "--oauth-token-type", "jwt"]
@@ -183,6 +200,22 @@ services:
       - keycloak-tokens:/app/data
       - keycloak-oauth-storage:/app/.oauth
 
+  qdrant:
+    image: qdrant/qdrant:latest
+    restart: always
+    ports:
+      - 127.0.0.1:6333:6333  # REST API
+      - 127.0.0.1:6334:6334  # gRPC (optional)
+    volumes:
+      - qdrant-data:/qdrant/storage
+    environment:
+      - QDRANT__SERVICE__API_KEY=${QDRANT_API_KEY:-my_secret_api_key}
+    healthcheck:
+      test: ["CMD-SHELL", "curl -f http://localhost:6333/readyz || exit 1"]
+      interval: 10s
+      timeout: 5s
+      retries: 10
+
 volumes:
   nextcloud:
   db:
@@ -190,3 +223,4 @@ volumes:
   oauth-tokens:
   keycloak-tokens:
   keycloak-oauth-storage:
+  qdrant-data: