fix: include url in web_extract trimmed results & fix docs

The web_extract_tool was stripping the 'url' key during its output
trimming step, but documentation in 3 places claimed it was present.
This caused KeyError when accessing result['url'] in execute_code
scripts, especially when extracting from multiple URLs.

Changes:
- web_tools.py: Add 'url' back to trimmed_results output
- code_execution_tool.py: Add 'title' to _TOOL_STUBS docstring and
  _TOOL_DOC_LINES so docs match actual {url, title, content, error}
  response format

tools/code_execution_tool.py

@@ -78,7 +78,7 @@ _TOOL_STUBS = {
     "web_extract": (
         "web_extract",
         "urls: list",
-        '"""Extract content from URLs. Returns dict with results list of {url, content, error}."""',
+        '"""Extract content from URLs. Returns dict with results list of {url, title, content, error}."""',
         '{"urls": urls}',
     ),
     "read_file": (
@@ -605,7 +605,7 @@ _TOOL_DOC_LINES = [
      "    Returns {\"data\": {\"web\": [{\"url\", \"title\", \"description\"}, ...]}}"),
     ("web_extract",
      "  web_extract(urls: list[str]) -> dict\n"
-     "    Returns {\"results\": [{\"url\", \"content\", \"error\"}, ...]} where content is markdown"),
+     "    Returns {\"results\": [{\"url\", \"title\", \"content\", \"error\"}, ...]} where content is markdown"),
     ("read_file",
      "  read_file(path: str, offset: int = 1, limit: int = 500) -> dict\n"
      "    Lines are 1-indexed. Returns {\"content\": \"...\", \"total_lines\": N}"),