feat: add RAG search endpoint with content extraction

- Add /rag/search endpoint for web, news, and image search via SearXNG
- Add /content/extract and /content/extract/batch endpoints
- Add ContentExtractor client using Trafilatura for content extraction
- Enhance HybridRAG web search with full content extraction
- Add Redis caching for search results
- Add new configuration options for search and extraction timeouts

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/core/dependencies.py

@@ -13,12 +13,15 @@ from typing import Annotated
 from fastapi import Depends
 import logging
 
+import redis.asyncio as aioredis
+
 from src.config import Settings, get_settings
 from src.clients.neo4j_client import Neo4jClient
 from src.clients.qdrant_client import QdrantClientWrapper
 from src.clients.wikijs_client import WikiJSClient
 from src.clients.searxng_client import SearXNGClient
 from src.clients.ollama_client import OllamaClient
+from src.clients.content_extractor import ContentExtractor
 
 logger = logging.getLogger(__name__)
 
@@ -116,6 +119,43 @@ def get_ollama_client() -> OllamaClient:
     return client
 
 
+@lru_cache
+def get_redis_client() -> aioredis.Redis:
+    """
+    Get Redis client singleton for caching.
+
+    Returns:
+        Async Redis client connected to the configured database
+
+    Note: Uses Redis DB 4 (configured for library-desk)
+    """
+    settings = get_settings()
+    client = aioredis.from_url(
+        settings.redis_url,
+        encoding="utf-8",
+        decode_responses=True
+    )
+    logger.debug(f"Created Redis client: {settings.redis_url}")
+    return client
+
+
+@lru_cache
+def get_content_extractor() -> ContentExtractor:
+    """
+    Get ContentExtractor singleton.
+
+    Returns:
+        Initialized content extraction client using Trafilatura
+    """
+    settings = get_settings()
+    extractor = ContentExtractor(
+        timeout=settings.content_extraction_timeout,
+        max_length=settings.content_max_length
+    )
+    logger.debug("Created ContentExtractor instance")
+    return extractor
+
+
 # Type aliases for FastAPI endpoint dependencies
 # Usage: def my_endpoint(neo4j: Neo4jDep):
 Neo4jDep = Annotated[Neo4jClient, Depends(get_neo4j_client)]
@@ -123,6 +163,8 @@ QdrantDep = Annotated[QdrantClientWrapper, Depends(get_qdrant_client)]
 WikiJSDep = Annotated[WikiJSClient, Depends(get_wikijs_client)]
 SearXNGDep = Annotated[SearXNGClient, Depends(get_searxng_client)]
 OllamaDep = Annotated[OllamaClient, Depends(get_ollama_client)]
+RedisDep = Annotated[aioredis.Redis, Depends(get_redis_client)]
+ContentExtractorDep = Annotated[ContentExtractor, Depends(get_content_extractor)]
 
 
 # Lifecycle management functions
@@ -336,6 +378,19 @@ def get_hybrid_rag_service() -> "HybridRAGService":
         graph_service=get_graph_service(),
         searxng_client=get_searxng_client(),
         ollama_client=get_ollama_client(),
+        content_extractor=get_content_extractor(),
+        settings=get_settings()
+    )
+
+
+@lru_cache
+def get_rag_search_service() -> "RAGSearchService":
+    """Get RAGSearchService singleton."""
+    from src.services.rag_search_service import RAGSearchService
+    return RAGSearchService(
+        searxng_client=get_searxng_client(),
+        content_extractor=get_content_extractor(),
+        redis_client=get_redis_client(),
         settings=get_settings()
     )