fix(docs[ext]): Log warnings when tool module collection fails

why: _collect_tools silently swallowed all exceptions with bare
except/pass, hiding import errors and causing missing tools in docs
without any warning. Contradicts the project's fail-closed philosophy.
what:
- Add logging import and module-level logger
- Replace except/pass with logger.warning including exc_info

Author: tony

docs/_ext/fastmcp_autodoc.py

@@ -25,6 +25,7 @@
 
 import importlib
 import inspect
+import logging
 import re
 import typing as t
 from dataclasses import dataclass
@@ -38,6 +39,8 @@
     from sphinx.domains.std import StandardDomain
     from sphinx.util.typing import ExtensionMetadata
 
+logger = logging.getLogger(__name__)
+
 # ---------------------------------------------------------------------------
 # Constants
 # ---------------------------------------------------------------------------
@@ -529,7 +532,11 @@ def _collect_tools(app: Sphinx) -> None:
             if hasattr(mod, "register"):
                 mod.register(collector)
         except Exception:
-            pass  # Module not importable during docs build
+            logger.warning(
+                "fastmcp_autodoc: failed to load tool module %s",
+                mod_name,
+                exc_info=True,
+            )
 
     app.env.fastmcp_tools = {tool.name: tool for tool in collector.tools}  # type: ignore[attr-defined]