Changed-files list for parallel sessions doesn't auto-update, only on manual refresh

In the VS Code extension, when a parallel Claude Code session is actively editing files (same working directory, no worktree involved), the list of changed files for that session used to update live as edits happened.

Now it only appears/updates after a manual refresh (e.g. reopening the panel or reloading the window) — it doesn't reflect new changes automatically while the parallel session is still running.

Steps to reproduce:

1. Open a repo in VS Code with the Claude Code extension.
2. Start a parallel/background session that edits files in the same repo.
3. Watch the changed-files list for that session in the UI while it's editing.

Expected: the list updates live as files change.
Actual: the list stays stale until a manual refresh/reload.

Environment: macOS (Darwin 22.6.0), VS Code extension.