fix: relaunch button could silently quit without reopening

[Alfredoalv13]

Summary

• PR fix: relaunch via open instead of app.relaunch() so TCC grants are seen #11 fixed `relaunch-app` to spawn `open ` instead of `app.relaunch()` so the new process gets proper independent TCC launch lineage.
• Verified directly this session that doing so and then immediately calling `app.exit(0)` can silently drop the relaunch entirely - the app quits and never reopens, with no error surfaced anywhere. Reproduced the exact same spawn+exit code as a standalone Node script and confirmed it works fine there, isolating the cause to `app.exit()` itself: it tears the process down harder/faster than a normal quit and was winning the race against `open` handing off to launchd.
• Fix: wait briefly (500ms) after spawning before calling `app.exit(0)`, and use the absolute `/usr/bin/open` path instead of relying on PATH resolution.

Test plan

• `tsc --noEmit` clean
• `npm test` - 94/94 files, 818/818 tests passing
• Manual: click "Quit & Reopen" from the permission banner several times in a row, confirm the app reliably reopens every single time (not just most of the time)