New patterns added to repair_broken_tool_calls():

1. Pattern 4: <tool><function>NAME</function><parameters>XML</parameters></tool>
   - Converts XML parameters to JSON format
   - Fills missing required params (e.g., path for list_files)

2. Pattern 0a: <tool><NAME><params></NAME></tool> (with closing tool name tag)
   - Handles format with closing tag for tool name

3. Expanded guard to detect known tool names used as wrapper tags
   - Now detects <fetch_instructions>, <list_files>, etc.

4. Fixed closure bug in Pattern -2 (wrong wrapper tags)
   - Used default argument to capture loop variable correctly

5. Post-processing: Fill missing required parameters
   - list_files gets path='.' if missing
   - search_files gets path='.' if missing

All 6 test cases pass:
- <tool><function>list_files</function><parameters>...</parameters></tool> -> OK
- <fetch_instructions><task>read_file</task>...</fetch_instructions> -> OK
- <tool_call><list_files></list_files></tool_call> -> OK
- <tool><list_files><path>.</path></list_files></tool> -> OK
- Valid JSON passthrough -> OK
- Missing required params auto-filled -> OK