- Replace `finally` with `catch` in [id].tsx handleSave so goBack is
not called when updateTask/setTagsForTask fails
- Extract shared goBack helper into src/lib/navigation.ts
- Both [id].tsx and new.tsx now import goBack from the shared module
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replace all router.back() calls with a goBack() helper that checks
router.canGoBack() first and falls back to router.replace('/') when
there is no screen to return to. In the task edit screen, change
catch to finally so the save button always resets its disabled state
even if updateTask/setTagsForTask throws.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>