Brings windows-support up to date with main (T-404/405/406, T-413–416,
T-421, the T-422 workspace-lifecycle epic, and the 2.4.0 release).
Conflict resolutions:
- terminal_pane.dart: keep the Windows PowerShell shell selection and
main's workspace-cwd fix (T-381) together.
- tool_check.dart: accept main's deletion (dead, unreferenced code).
- CHANGELOG.md: keep both Unreleased sections.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
jpmschweitzerandClaude Opus 4.8
84a6ef7c77