[Frontend] Add unsaved-consent-change protection

## Problem
Permission and emergency-profile edits can be abandoned through navigation, leaving users unsure whether the new visibility settings were saved.
## Acceptance criteria
- Dirty state is tracked per form section and reset only after confirmed server success.
- Navigation warnings are accessible and do not block safe programmatic redirects.
- Failed saves preserve edits without duplicating requests.
- Tests cover browser back, tab close, refresh, concurrent update, and mobile viewport behavior.

Start by locating the permission and emergency-profile form sections, their save handlers, and the navigation handlers that can abandon edits. Read the existing form and navigation tests, then add coverage for browser back, tab close, refresh, concurrent updates, and mobile viewports. Done means section-level dirty state resets only after confirmed success, failed saves preserve edits without duplicate requests, and warnings remain accessible without blocking safe programmatic redirects.

Written by the indexing model from the issue text.