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/iosMain/kotlin/com/example/casera/platform/ContractorImportHandler.ios.kt

@@ -0,0 +1,17 @@
+package com.example.casera.platform
+
+import androidx.compose.runtime.Composable
+import com.example.casera.models.Contractor
+
+/**
+ * iOS implementation is a no-op - import is handled in Swift layer via ContractorSharingManager.swift.
+ * The iOS iOSApp.swift handles file imports directly.
+ */
+@Composable
+actual fun ContractorImportHandler(
+    pendingContractorImportUri: Any?,
+    onClearContractorImport: () -> Unit,
+    onImportSuccess: (Contractor) -> Unit
+) {
+    // No-op on iOS - import handled in Swift layer
+}

composeApp/src/iosMain/kotlin/com/example/casera/platform/ContractorSharing.ios.kt

@@ -0,0 +1,15 @@
+package com.example.casera.platform
+
+import androidx.compose.runtime.Composable
+import com.example.casera.models.Contractor
+
+/**
+ * iOS implementation is a no-op - sharing is handled in Swift layer via ContractorSharingManager.swift.
+ * The iOS ContractorDetailView uses the Swift sharing manager directly.
+ */
+@Composable
+actual fun rememberShareContractor(): (Contractor) -> Unit {
+    return { _: Contractor ->
+        // No-op on iOS - sharing handled in Swift layer
+    }
+}