fix: relaunch via open instead of app.relaunch() so TCC grants are seen

[Alfredoalv13]

Summary

• PR fix: replace dead permission-refresh button with real Quit & Reopen #10 added a "Quit & Reopen" button using `app.relaunch()` to work around macOS caching permission-check results for the life of a process.
• Verified directly this session that `app.relaunch()` doesn't actually fix the problem it was meant to fix: a relaunched process kept reporting Screen Recording/Accessibility as denied immediately after the same grant was confirmed fresh in System Settings, while the identical signed binary launched via `open` (same mechanism Finder/Dock use) correctly saw the grant every single time.
• Root cause: `app.relaunch()` re-execs the new process from the current one instead of handing off through launchd, and TCC's authorization resolution for the new process was still keying off the old (denied) process's context on this system.
• Fix: on macOS, shell out to `open ` (detached) then `app.exit()`, instead of `app.relaunch()`. Other platforms unchanged.

Test plan

• `tsc --noEmit` clean
• `npm test` - 94/94 files, 817/817 tests passing
• Manual: grant Screen Recording in System Settings while VybeClip is open and denied, click "Quit & Reopen", confirm the banner clears on the very first relaunch (not requiring a second manual quit)