Add comprehensive error message parsing to prevent raw JSON display

- Created ErrorMessageParser utility for both iOS (Swift) and Android (Kotlin)
- Parser detects JSON-formatted error messages and extracts user-friendly text
- Identifies when data objects (not errors) are returned and provides generic messages
- Updated all API error handling to pass raw error bodies instead of concatenating
- Applied ErrorMessageParser across all ViewModels and screens on both platforms
- Fixed ContractorApi and DocumentApi to not concatenate error bodies with messages
- Updated ApiResultHandler to automatically parse all error messages
- Error messages now show "Request failed. Please check your input and try again." instead of raw JSON

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

iosApp/iosApp/Task/CompleteTaskView.swift

@@ -278,6 +278,10 @@ struct CompleteTaskView: View {
             .onAppear {
                 contractorViewModel.loadContractors()
             }
+            .handleErrors(
+                error: errorMessage,
+                onRetry: { handleComplete() }
+            )
         }
     }
 

iosApp/iosApp/Task/EditTaskView.swift

@@ -128,6 +128,10 @@ struct EditTaskView: View {
             .onAppear {
                 loadLookups()
             }
+            .handleErrors(
+                error: viewModel.errorMessage,
+                onRetry: { submitForm() }
+            )
         }
     }
 
@@ -181,3 +185,4 @@ struct EditTaskView: View {
         }
     }
 }
+

iosApp/iosApp/Task/TaskViewModel.swift

@@ -49,7 +49,7 @@ class TaskViewModel: ObservableObject {
                     break
                 } else if let error = state as? ApiResultError {
                     await MainActor.run {
-                        self.errorMessage = error.message
+                        self.errorMessage = ErrorMessageParser.parse(error.message)
                         self.isLoading = false
                     }
                     sharedViewModel.resetAddTaskState()