Add contractor management and integrate with task completions

Features:
- Add full contractor CRUD functionality (Android & iOS)
- Add contractor selection to task completion dialog
- Display contractor info in completion cards
- Add ContractorSpecialty model and API integration
- Add contractors tab to bottom navigation
- Replace hardcoded specialty lists with API data
- Update lookup endpoints to return arrays instead of paginated responses

Changes:
- Add Contractor models (ContractorSummary, ContractorDetail, ContractorCreate/UpdateRequest)
- Add ContractorApi with endpoints for list, detail, create, update, delete, toggle favorite
- Add ContractorViewModel for state management
- Add ContractorsScreen and ContractorDetailScreen for Android
- Add AddContractorDialog with form validation
- Add Contractor views for iOS (list, detail, form)
- Update CompleteTaskDialog to include contractor selection
- Update CompletionCardView to show contractor name and phone
- Add contractor field to TaskCompletion model
- Update LookupsApi to return List<T> instead of paginated responses
- Update LookupsRepository and LookupsViewModel to handle array responses
- Update LookupsManager (iOS) to handle array responses for contractor specialties

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

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

composeApp/src/commonMain/kotlin/com/example/mycrib/models/Lookups.kt

@@ -72,3 +72,15 @@ data class TaskCategory(
     val name: String,
     val description: String? = null
 )
+
+@Serializable
+data class ContractorSpecialtyResponse(
+    val count: Int,
+    val results: List<ContractorSpecialty>
+)
+
+@Serializable
+data class ContractorSpecialty(
+    val id: Int,
+    val name: String
+)