Add residence picker to contractor create/edit screens

Kotlin/KMM:
- Update Contractor model with optional residenceId and specialties array
- Rename averageRating to rating, update address field names
- Add ContractorMinimal model for task references
- Add residence picker and multi-select specialty chips to AddContractorDialog
- Fix ContractorsScreen and ContractorDetailScreen field references

iOS:
- Rewrite ContractorFormSheet with residence and specialty pickers
- Update ContractorDetailView with FlowLayout for specialties
- Add FlowLayout component for wrapping badge layouts
- Fix ContractorCard and CompleteTaskView field references
- Update ContractorFormState with residence/specialty selection

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

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

iosApp/iosApp/Task/CompleteTaskView.swift

@@ -428,11 +428,11 @@ struct ContractorPickerView: View {
                                             .foregroundStyle(.secondary)
                                     }
 
-                                    if let specialty = contractor.specialty {
+                                    if let firstSpecialty = contractor.specialties.first {
                                         HStack(spacing: 4) {
                                             Image(systemName: "wrench.and.screwdriver")
                                                 .font(.caption2)
-                                            Text(specialty)
+                                            Text(firstSpecialty.name)
                                                 .font(.caption2)
                                         }
                                         .foregroundStyle(.tertiary)