Summary

• add a custom NSIS recovery path for legacy Windows uninstall failures instead of leaving users with a generic "cannot close" message
• bundle a legacy cleanup helper next to Windows release artifacts so support and users can repair broken <=3.1.x installs without manual registry spelunking
• tighten app shutdown cleanup on quit by closing long-lived resources before uninstall/upgrade retries
• add focused tests for the installer include and cleanup helper packaging

Why we intentionally do not delete all AppData on uninstall

We are keeping deleteAppDataOnUninstall: false on purpose.

From the user point of view, uninstall + reinstall is often a repair path, not a request to erase all personal state. If we delete AppData by default, we would silently wipe user-owned data such as configuration, provider/API setup, local history/database, and other runtime state that users expect to survive a reinstall.

The safer default is:

• remove app binaries during uninstall
• preserve user data by default
• provide an explicit cleanup path when someone truly wants a full reset

This PR follows that model by shipping a dedicated legacy cleanup helper. Users/support can run it normally to remove broken install leftovers while keeping data, or opt into a stronger reset with -RemoveAppData when they explicitly want everything cleared.

Validation

• npm.cmd test -- --run tests/build-windows-script.test.ts tests/build-windows-artifacts.test.ts tests/windows-legacy-uninstall-remediation.test.ts

Notes

• I also attempted tsc --noEmit in the PR worktree, but the local environment currently reports an unrelated missing module issue for rehype-sanitize.