Add delete account feature to mobile app

- DELETE /api/auth/account/ API call in AuthApi + APILayer
- authProvider field on User model for email vs social auth detection
- DeleteAccountDialog with password (email) or "type DELETE" (social) confirmation
- Red "Delete Account" card on ProfileScreen
- Navigation wired in App.kt (clears data, returns to login)
- 10 i18n strings in strings.xml
- ViewModel unit tests for delete account state

composeApp/src/commonTest/kotlin/com/tt/honeyDue/viewmodel/AuthViewModelTest.kt

@@ -56,4 +56,27 @@ class AuthViewModelTest {
         // Then
         assertIs<ApiResult.Idle>(viewModel.registerState.value)
     }
+
+    // MARK: - Delete Account Tests
+
+    @Test
+    fun testInitialDeleteAccountState() {
+        // Given
+        val viewModel = AuthViewModel()
+
+        // Then
+        assertIs<ApiResult.Idle>(viewModel.deleteAccountState.value)
+    }
+
+    @Test
+    fun testResetDeleteAccountState() {
+        // Given
+        val viewModel = AuthViewModel()
+
+        // When
+        viewModel.resetDeleteAccountState()
+
+        // Then
+        assertIs<ApiResult.Idle>(viewModel.deleteAccountState.value)
+    }
 }