feat: migrate web search from tatlock_core to Librarian

Move web search functionality to The Librarian agent, integrating with
the library-desk /rag/search endpoint for enhanced search capabilities.

Changes:
- Add search_web, read_url, read_urls_batch tools to Librarian
- Add WebSearchResult, ContentExtractionResult models to client
- Add search_web, extract_content, extract_content_batch client methods
- Update Librarian capability with web/url/internet domains
- Remove search_web from tatlock_core tools and toolset
- Update Tatlock system prompt to delegate web search to Librarian
- Add comprehensive unit tests for new Librarian tools
- Clean up legacy src/agents/tools.py

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

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

src/agents/tools.py

@@ -4,20 +4,14 @@ Tatlock's permanent tools.
 These tools are always available to the butler agent:
 - Calculator: For all mathematical operations
 - Date/Time toolkit: For current time and time calculations
-- SearXNG search: For searching the web for current information
+
+Note: Web search has been moved to The Librarian agent.
+See src/agents/librarian/tools.py for search_web functionality.
 """
 
-import logging
 import math
 import re
 from datetime import datetime, timedelta
-from typing import Any
-
-import httpx
-
-from src.core.config import config
-
-logger = logging.getLogger(__name__)
 
 
 # ============================================================================
@@ -256,91 +250,3 @@ def time_difference(date1_str: str, date2_str: str = "now") -> str:
 
     except Exception as e:
         return f"Error calculating time difference: {str(e)}"
-
-
-# ============================================================================
-# SearXNG Search Tool
-# ============================================================================
-
-async def search_web(query: str, num_results: int = 5) -> str:
-    """
-    Search the web using SearXNG.
-
-    Args:
-        query: Search query string
-        num_results: Number of results to return (default: 5, max: 10)
-
-    Returns:
-        Formatted search results as a string with titles, URLs, and snippets
-
-    Examples:
-        search_web("Python async programming") -> "1. Title: ...\n   URL: ...\n   ..."
-    """
-    try:
-        # Limit results
-        num_results = min(num_results, 10)
-
-        # Get SearXNG host with fallback logic
-        searxng_host = str(config.SEARXNG_HOST)
-
-        # Try production host first, fall back to localhost in development
-        hosts_to_try = [searxng_host]
-        if config.ENVIRONMENT.value == "development" and "localhost" not in searxng_host:
-            # Add localhost fallback for development
-            hosts_to_try.append("http://localhost:8087")
-
-        last_error = None
-
-        for host in hosts_to_try:
-            try:
-                logger.info(f"Attempting SearXNG search at {host}")
-
-                async with httpx.AsyncClient(timeout=config.SEARXNG_TIMEOUT) as client:
-                    response = await client.get(
-                        f"{host}/search",
-                        params={
-                            "q": query,
-                            "format": "json",
-                            "pageno": 1,
-                        }
-                    )
-
-                    if response.status_code == 200:
-                        data = response.json()
-                        results = data.get("results", [])
-
-                        if not results:
-                            return f"No results found for '{query}'"
-
-                        # Format results
-                        formatted_results = []
-                        for i, result in enumerate(results[:num_results], 1):
-                            title = result.get("title", "No title")
-                            url = result.get("url", "")
-                            content = result.get("content", "No description available")
-
-                            formatted_results.append(
-                                f"{i}. {title}\n"
-                                f"   URL: {url}\n"
-                                f"   {content}\n"
-                            )
-
-                        return "\n".join(formatted_results)
-                    else:
-                        last_error = f"SearXNG returned status {response.status_code}"
-
-            except httpx.ConnectError:
-                last_error = f"Cannot connect to SearXNG at {host}"
-                logger.warning(f"SearXNG connection failed at {host}, trying next host if available")
-                continue
-            except Exception as e:
-                last_error = str(e)
-                logger.warning(f"SearXNG error at {host}: {e}")
-                continue
-
-        # All hosts failed
-        return f"Error searching: {last_error}. Please check that SearXNG is running."
-
-    except Exception as e:
-        logger.error(f"Unexpected error in search_web: {e}", exc_info=True)
-        return f"Error searching: {str(e)}"