Copilot Chat session not discoverable, then later appears as Archived in related workspace

- Copilot Chat Extension Version: Unknown from UI, likely current stable in VS Code 1.132.0 session
- - VS Code Version: 1.132.0
- - - OS Version: Windows
- - - - Feature (e.g. agent/edit/ask mode): Copilot Chat sessions list / session archive visibility
- - - - - Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): GPT-5.3-Codex (as reported in assistant session)
- - - - - - Logs:
- - - - - - - Session behavior showed inconsistent discoverability across related workspace contexts.
- - - - - - - - A session expected in active list later appeared under Archived without clear transition context.
- - - - - - - - - Earlier attempts to locate/recover session from another workspace context failed, then session later became visible as archived.
### Summary
A Copilot Chat session was not discoverable when expected in one workspace context, then later showed up in the Archived section. This created confusion and perceived risk of data loss.

### Environment
- OS: Windows
- - VS Code: 1.132.0
- - - Workspace type: multi-root
- - - - Related folders:
- - - - - C:\Users\wcull\flows_Equip_Isolation
- - - - - - C:\Users\wcull\flows_PID_Extractor
### Observed behavior
1. Session expected from active work was not visible in the expected workspace/session list.
2. 2. Visibility behavior appeared inconsistent across workspace contexts.
3. 3. Later, the same session appeared under Archived:
4. - equipment_isolation_chat_5_extends_fastest_way_to_build_a_data_model
### Expected behavior
- Session visibility should be consistent across related workspace context views.
- - Archive state should be predictable and should not appear to change unexpectedly.
- - - If a session is moved to Archived, the UI should clearly indicate why and when.
### Steps to Reproduce
1. Work in one VS Code workspace and create/use a Copilot chat session.
2. 2. Open a related workspace and try to locate that same session.
3. 3. Session is not discoverable in active list as expected.
4. 4. Later refresh/reopen session list and observe session appear under Archived.
### Impact
- Workflow interruption.
- - Time spent recovering session context from transcript files.
- - - Reduced confidence in session persistence/discoverability.
### Local evidence
- Transcript file:
- - C:\Users\wcull\flows_Equip_Isolation\recovered_chat_equipment_isolation_chat_5_extends_fastest_way_to_build_a_data_model_full.txt
- - - Screenshot showing session in Archived section (available).