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/tatlock.py

@@ -17,7 +17,6 @@ from src.agents.tatlock_core.tools import (
     get_current_datetime,
     calculate_time_offset,
     time_difference,
-    search_web,
 )
 from src.core.config import config
 from src.core.logging_config import get_logger
@@ -76,18 +75,17 @@ You have direct access to several permanent tools that you should USE whenever a
    - time_difference: Calculate the time between two dates
    - Use these for ANY date/time queries - never guess at dates or times
 
-3. **Web Search** (search_web): Search for current, volatile, or factual information
-   - Use this for ANY information that might be current, factual, or outside your training data
+3. **Web Search** (via Librarian): For current, volatile, or factual information
+   - Delegate to the Librarian for web searches and research
    - Examples: news, current events, recent developments, specific facts, technical documentation
-   - Always prefer searching over guessing or using potentially outdated knowledge
-   - For extensive research questions, note that this will later be delegated to the librarian
+   - Use: delegate_to_librarian(task="search the web for ...")
 
 ## Tool Usage Guidelines
 
 - **Mathematics**: ALWAYS use the calculator tool, even for simple arithmetic
 - **Dates/Times**: ALWAYS use the date/time tools, never guess or estimate
-- **Current Information**: ALWAYS search for facts, news, or volatile information
-- **Verification**: When facts are important, use search to verify rather than rely on memory alone
+- **Current Information**: Delegate web searches to the Librarian
+- **Verification**: When facts are important, delegate to Librarian for research
 - When you use a tool, explain what you're doing in a butler-appropriate manner
 - Present tool results naturally in your response
 
@@ -238,28 +236,8 @@ class TatlockAgent(AgentInterface):
                 ctx.deps.log_call(f"🕐 Calculating time difference between {date1_str} and {date2_str}")
             return time_difference(date1_str, date2_str)
 
-        # Web search tool
-        @self._agent.tool
-        async def web_search(ctx: RunContext[ToolCallTracker], query: str, num_results: int = 5) -> str:
-            """
-            Search the web using SearXNG for current information.
-
-            Use this tool for ANY information that might be:
-            - Current or time-sensitive (news, events, recent developments)
-            - Factual and verifiable (statistics, technical specs, definitions)
-            - Outside your training data or knowledge cutoff
-
-            Args:
-                query: Search query string
-                num_results: Number of results to return (default: 5, max: 10)
-
-            Returns:
-                Formatted search results with titles, URLs, and snippets
-            """
-            # Log the search query to reasoning output
-            if ctx.deps:
-                ctx.deps.log_call(f"🔍 Searching for: '{query}'")
-            return await search_web(query, num_results)
+        # NOTE: Web search has been moved to The Librarian agent.
+        # Use delegate_to_librarian(task="search web for ...") for web search.
 
     @property
     def agent(self):