Log MCPServer handler exceptions by kind and keep crash details off the wire (#3314)

Co-authored-by: Marcelo Trylesinski <marcelotryle@gmail.com>

docs_src/uri_templates/tutorial002.py

@@ -1,6 +1,7 @@
 from pathlib import Path
 
 from mcp.server import MCPServer
+from mcp.server.mcpserver.exceptions import ResourceNotFoundError
 from mcp.shared.path_security import safe_join
 
 mcp = MCPServer("Bookshop")
@@ -11,4 +12,7 @@ DOCS_ROOT = Path("./manuals")
 @mcp.resource("manuals://{+path}")
 def read_manual(path: str) -> str:
     """A staff manual page, served from a directory on disk."""
-    return safe_join(DOCS_ROOT, path).read_text(encoding="utf-8")
+    file = safe_join(DOCS_ROOT, path)
+    if not file.is_file():
+        raise ResourceNotFoundError(f"No manual at {path!r}.")
+    return file.read_text(encoding="utf-8")