Copilot Agents have lost Tool access despite Tools enabled

- Copilot Chat Extension Version:
- VS Code Version: 1.137.0
- OS Version: Windows 11 (Windows 10.0.26220)
- Feature (e.g. agent/edit/ask mode): Agent
- Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): Auto (or any)
- Logs:

Steps to Reproduce:

1. New session
2. Agent mode (not a custom agent), Auto or any model

3. Review tools enabled, disable all, enable all "Built-In" tools including edit

4. Ask agent to emit a simple text into a file.

5. Agent does not have access to edit files and will fall back to terminal/shell commands:

Chat Debug shows only 33 tools enabled and edit files is not in the list:

```
tools (33) : memory, read_file, session_store_sql, view_image, vscode_askQuestions,
get_terminal_output, kill_terminal, run_in_terminal, runSubagent, send_to_terminal,
tool_search, create_new_workspace, copilot_getNotebookSummary, github_text_search,
install_extension, read_notebook_cell_output, resolve_memory_file_uri,
run_notebook_cell, run_vscode_command, click_element, create_and_run_task,
drag_element, get_task_output, handle_dialog, hover_element, navigate_page,
open_browser_page, read_page, run_playwright_code, screenshot_page,
terminal_last_command, terminal_selection, type_in_page
```

I *presume* it's just me, but I uninstalled all my MCPs and extensions, restarted, no dice. Cleared out my user JSON settings. Restarted, no dice.

Help?