Add contractor sharing feature and move settings to navigation bar

Contractor Sharing:
- Add .casera file format for sharing contractors between users
- Create SharedContractor model with JSON serialization
- Implement ContractorSharingManager for iOS (Swift) and Android (Kotlin)
- Register .casera file type in iOS Info.plist and Android manifest
- Add share button to ContractorDetailView (iOS) and ContractorDetailScreen (Android)
- Add import confirmation, success, and error dialogs
- Create expect/actual platform implementations for sharing and import handling

Navigation Changes:
- Remove Profile tab from bottom tab bar (iOS and Android)
- Add settings gear icon to left side of "My Properties" title
- Settings gear opens Profile/Settings screen as sheet (iOS) or navigates (Android)
- Add property button to top right action bar

Bug Fixes:
- Fix ResidenceUsersResponse to match API's flat array response format
- Fix GenerateShareCodeResponse handling to access nested shareCode property
- Update ManageUsersDialog to accept residenceOwnerId parameter

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

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

composeApp/src/commonMain/kotlin/com/example/casera/data/DataManager.kt

@@ -205,6 +205,11 @@ object DataManager {
     private val _lastSyncTime = MutableStateFlow(0L)
     val lastSyncTime: StateFlow<Long> = _lastSyncTime.asStateFlow()
 
+    // ==================== SEEDED DATA ETAG ====================
+
+    private val _seededDataETag = MutableStateFlow<String?>(null)
+    val seededDataETag: StateFlow<String?> = _seededDataETag.asStateFlow()
+
     // ==================== INITIALIZATION ====================
 
     /**
@@ -584,6 +589,34 @@ object DataManager {
         _lookupsInitialized.value = true
     }
 
+    /**
+     * Set all lookups from unified seeded data response.
+     * Also stores the ETag for future conditional requests.
+     */
+    fun setAllLookupsFromSeededData(seededData: SeededDataResponse, etag: String?) {
+        setResidenceTypes(seededData.residenceTypes)
+        setTaskFrequencies(seededData.taskFrequencies)
+        setTaskPriorities(seededData.taskPriorities)
+        setTaskStatuses(seededData.taskStatuses)
+        setTaskCategories(seededData.taskCategories)
+        setContractorSpecialties(seededData.contractorSpecialties)
+        setTaskTemplatesGrouped(seededData.taskTemplates)
+        setSeededDataETag(etag)
+        _lookupsInitialized.value = true
+    }
+
+    /**
+     * Set the ETag for seeded data. Used for conditional requests.
+     */
+    fun setSeededDataETag(etag: String?) {
+        _seededDataETag.value = etag
+        if (etag != null) {
+            persistenceManager?.save(KEY_SEEDED_DATA_ETAG, etag)
+        } else {
+            persistenceManager?.remove(KEY_SEEDED_DATA_ETAG)
+        }
+    }
+
     fun markLookupsInitialized() {
         _lookupsInitialized.value = true
     }
@@ -632,6 +665,7 @@ object DataManager {
         _taskTemplates.value = emptyList()
         _taskTemplatesGrouped.value = null
         _lookupsInitialized.value = false
+        _seededDataETag.value = null
 
         // Clear cache timestamps
         residencesCacheTime = 0L
@@ -723,6 +757,11 @@ object DataManager {
             manager.load(KEY_HAS_COMPLETED_ONBOARDING)?.let { data ->
                 _hasCompletedOnboarding.value = data.toBooleanStrictOrNull() ?: false
             }
+
+            // Load seeded data ETag for conditional requests
+            manager.load(KEY_SEEDED_DATA_ETAG)?.let { data ->
+                _seededDataETag.value = data
+            }
         } catch (e: Exception) {
             println("DataManager: Error loading from disk: ${e.message}")
         }
@@ -733,4 +772,5 @@ object DataManager {
 
     private const val KEY_CURRENT_USER = "dm_current_user"
     private const val KEY_HAS_COMPLETED_ONBOARDING = "dm_has_completed_onboarding"
+    private const val KEY_SEEDED_DATA_ETAG = "dm_seeded_data_etag"
 }