GitHub Copilot resubmission of past prompt using Agent custom prompt still leaves tools disabled

1. Create a read-only agent named "Talk", e.g.
```markdown
---
name: Talk
description: Talk without doing anything.
tools: ['execute/getTerminalOutput', 'execute/runInTerminal', 'read', 'search', 'web']
---
Talk about it.
```
2. Create a writable agent "Do", e.g.
```markdown
---
name: Do
description: Do something
agent: agent
---
Do something about it.
```
3. Issue a prompt using "Talk", e.g.
> /talk Go fix the bugs.
4. The agent will have trouble editing files, so stop the output, edit the previous prompt, and resubmit it using "Do", e.g.
> /do Go fix the bugs.

**Expected:** The agent will be able to edit files.

**Actual:** The agent still cannot edit files because the tools have not been enabled. Apparently the tool settings for the custom prompt "Talk" got "stuck" on the prompt, even when it was resubmitted using the "Do" agent with a different tool set.

```
Version: 1.137.0 (user setup)
Commit: 645f29cc3176500b4b5762ba887cf2a7f0ffdf2c
Date: 2026-09-08T13:43:59-07:00
Electron: 42.10.0
ElectronBuildId: 15109253
Chromium: 148.0.7778.280
Node.js: 24.18.1
V8: 14.8.178.38-electron.0
@github/copilot: 1.0.84.70.gdb75d0d
@github/copilot-sdk: 1.0.13-preview.4
OS: Windows_NT x64 10.0.26200
```