Copilot Chat session is lost after VS Code crash only when workspace is opened via \\wsl.localhost on Windows (no Remote-WSL)

Type: Bug

Summary
When VS Code crashes, Copilot Chat conversations are not recovered and the chat history appears empty after restart.

This reproduces only when the workspace is opened from the WSL filesystem through a Windows UNC path (for example \\wsl.localhost\Ubuntu\home\\) in a normal Windows VS Code window (without Remote-WSL).

Reproduction Steps
1. On Windows, open a project using a UNC WSL path, e.g. \\wsl.localhost\Ubuntu\home\\.
2. Make sure VS Code is not connected using Remote-WSL (no WSL remote context).
3. Use Copilot Chat for a while and create one or more conversations.
4. Let VS Code crash (or force-close during an active session).
5. Reopen VS Code and the same workspace.
6. Open Copilot Chat/history.

Expected Behavior
Previous Copilot Chat sessions should be recoverable after restart/crash.

Actual Behavior
Copilot Chat appears empty, and previous sessions are missing / not recoverable.

Scenario Matrix
- Windows VS Code + workspace in WSL filesystem via \\wsl.localhost + no Remote-WSL: FAIL (chat/session lost after crash)
- VS Code connected with Remote-WSL: PASS (issue not observed)
- Windows VS Code + workspace on Windows filesystem (e.g. C:\...): PASS (issue not observed)

Environment
- VS Code: 1.127.0 (4fe60c8b1cdac1c4c174f2fb180d0d758272d713)
- OS: Windows
- Copilot Chat extension version: not captured

Related issues checked (possibly related, but not exact)
- https://github.com/microsoft/vscode/issues/302900
- https://github.com/microsoft/vscode/issues/285405
- https://github.com/microsoft/vscode-copilot-release/issues/9868

Key difference here: strict reproduction matrix tied to opening the project through \\wsl.localhost on Windows without Remote-WSL.