[Bug] session-store.db not created on Windows WSL2 — no persistent session storage

## Summary

On Windows with WSL2, Copilot CLI does not create `session-store.db` at the expected path (`~/.copilot/session-store.db`). This means session history is not persisted in a queryable format, breaking any tooling that depends on the session database for recall or analysis.

## Steps to reproduce

1. Install Copilot CLI on Windows (WSL2 Ubuntu)
2. Run several interactive sessions
3. Check for `~/.copilot/session-store.db`
4. File does not exist

## Expected behavior

Copilot CLI should create and maintain `~/.copilot/session-store.db` with session history (sessions, turns, session_files, checkpoints tables) — same as it does on macOS and native Linux.

## Actual behavior

- `~/.copilot/session-store.db` is never created
- Session state may exist only in `~/.copilot/session-state/*/events.jsonl` (ephemeral per-session files)
- No consolidated queryable database is available

## Why this matters

- **Session continuity:** Users cannot resume or reference prior sessions reliably
- **Ecosystem tooling:** Tools like [auto-memory/session-recall](https://github.com/dezgit2025/auto-memory) depend on `session-store.db` for context recall. Without it, Windows/WSL2 users are locked out of the session recall ecosystem.
- **Parity gap:** macOS users get full session persistence; Windows/WSL2 users do not

## Environment

- OS: Windows 11 + WSL2 (Ubuntu)
- Copilot CLI: v1.0.34+
- Shell: bash (WSL2)

## Related

- [dezgit2025/auto-memory#13](https://github.com/dezgit2025/auto-memory/issues/13) — Windows user unable to create .db file using WSL
- [dezgit2025/auto-memory#3](https://github.com/dezgit2025/auto-memory/issues/3) — session-store.db not found on fresh installs

## Possible causes

1. SQLite binary or filesystem permission issue in WSL2 (NTFS vs ext4 boundary)
2. Copilot CLI conditionally skipping DB creation on WSL2
3. Different storage backend used on Windows that does not consolidate into session-store.db