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/config.py

@@ -89,6 +89,15 @@ class Settings(BaseSettings):
     app_version: str = Field(default=__version__, description="Application version")
     debug: bool = Field(default=False, description="Debug mode")
 
+    # RAG Search Configuration
+    search_cache_ttl: int = Field(default=300, ge=0, le=3600, description="Search cache TTL in seconds")
+    search_timeout: int = Field(default=10, ge=1, le=60, description="SearXNG timeout in seconds")
+    search_default_limit: int = Field(default=10, ge=1, le=20, description="Default number of search results")
+
+    # Content Extraction Configuration
+    content_extraction_timeout: int = Field(default=5, ge=1, le=30, description="Trafilatura per-URL timeout in seconds")
+    content_max_length: int = Field(default=2000, ge=500, le=10000, description="Max extracted content length per result")
+
     @property
     def qdrant_url(self) -> str:
         """Computed Qdrant URL."""