feat(profile): implement user-initiated GDPR-compliant profile deletion

- Add DELETE /users/me endpoint with cascading data removal
- Implement frontend confirmation dialog and deletion flow
- Add audit logging for deletion requests
- Update localization files for new UI strings
- Add scheduled cleanup service for AI traces
- Document GDPR compliance in technical specification

BREAKING CHANGE: Users can now permanently delete their profiles and associated data

flutter/lib/l10n/app_sv.arb

@@ -521,5 +521,8 @@
   "logoutAction": "Logga ut",
   "adminAiDescription": "Översikt över AI-funktioner som backend exponerar.",
   "adminPagePrefix": "Sida: ",
-  "profileDatabaseDescription": "Databasfliken samlar dina huvudområden för lager och produkter."
+  "profileDeleteConfirmTitle": "Bekräfta radering",
+  "profileDeleteConfirmMessage": "Är du säker på att du vill ta bort din profil? Alla dina data kommer att raderas permanent.",
+  "profileDeleteAction": "Ta bort min profil",
+  "profileDeletedMessage": "Din profil har tagits bort."
 }