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/features/profile/data/profile_repository.dart

@@ -42,6 +42,14 @@ class ProfileRepository {
     return UserProfile.fromJson(data);
   }
 
+  Future<void> deleteMe() async {
+    final token = await _ref.read(authStateProvider.future);
+    await guardedApiCall(
+      _ref,
+      () => _apiClient.deleteJson(UserApiPaths.me, token: token),
+    );
+  }
+
   Future<void> refreshCategories() async {
     final token = await _ref.read(authStateProvider.future);
     await guardedApiCall(

flutter/lib/features/profile/presentation/profile_screen.dart

@@ -20,6 +20,7 @@ class _ProfileScreenState extends ConsumerState<ProfileScreen> {
   final _formKey = GlobalKey<FormState>();
   bool _isLoading = true;
   bool _isSaving = false;
+  bool _isDeleting = false;
   String? _error;
   UserProfile? _profile;
 
@@ -96,6 +97,61 @@ class _ProfileScreenState extends ConsumerState<ProfileScreen> {
     context.go('/login');
   }
 
+  Future<void> _showDeleteProfileConfirmation() async {
+    return showDialog<void>(
+      context: context,
+      barrierDismissible: false,
+      builder: (BuildContext context) {
+        return AlertDialog(
+          title: Text(context.l10n.profileDeleteConfirmTitle),
+          content: SingleChildScrollView(
+            child: ListBody(
+              children: <Widget>[
+                Text(context.l10n.profileDeleteConfirmMessage),
+              ],
+            ),
+          ),
+          actions: <Widget>[
+            TextButton(
+              child: Text(context.l10n.noLabel),
+              onPressed: () {
+                Navigator.of(context).pop();
+              },
+            ),
+            TextButton(
+              child: Text(context.l10n.deleteAction),
+              onPressed: () {
+                Navigator.of(context).pop();
+                _deleteProfile();
+              },
+            ),
+          ],
+        );
+      },
+    );
+  }
+
+  Future<void> _deleteProfile() async {
+    setState(() => _isDeleting = true);
+    try {
+      await ref.read(profileRepositoryProvider).deleteMe();
+      if (!mounted) return;
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(content: Text(context.l10n.profileDeletedMessage)),
+      );
+      await ref.read(authStateProvider.notifier).logout();
+      if (!mounted) return;
+      context.go('/login');
+    } catch (e) {
+      if (!mounted) return;
+      ScaffoldMessenger.of(context).showSnackBar(
+        buildCopyableErrorSnackBar(context, mapErrorToUserMessage(e, context)),
+      );
+    } finally {
+      if (mounted) setState(() => _isDeleting = false);
+    }
+  }
+
   Widget _buildProfileForm(BuildContext context, ThemeData theme) {
     return Form(
       key: _formKey,
@@ -286,6 +342,24 @@ class _ProfileScreenState extends ConsumerState<ProfileScreen> {
                     label: Text(context.l10n.logoutAction),
                   ),
                 ),
+                const SizedBox(height: 12),
+                SizedBox(
+                  width: double.infinity,
+                  child: FilledButton.icon(
+                    onPressed: _isDeleting ? null : _showDeleteProfileConfirmation,
+                    icon: _isDeleting
+                        ? const SizedBox(
+                            height: 20,
+                            width: 20,
+                            child: CircularProgressIndicator(strokeWidth: 2),
+                          )
+                        : const Icon(Icons.delete_forever_outlined),
+                    label: Text(context.l10n.profileDeleteAction),
+                    style: FilledButton.styleFrom(
+                      backgroundColor: Colors.red,
+                    ),
+                  ),
+                ),
               ],
             ),
           ),