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/wasmJsMain/kotlin/com/example/casera/platform/ContractorImportHandler.wasmJs.kt

@@ -0,0 +1,13 @@
+package com.example.casera.platform
+
+import androidx.compose.runtime.Composable
+import com.example.casera.models.Contractor
+
+@Composable
+actual fun ContractorImportHandler(
+    pendingContractorImportUri: Any?,
+    onClearContractorImport: () -> Unit,
+    onImportSuccess: (Contractor) -> Unit
+) {
+    // Not implemented for Wasm/Web
+}

composeApp/src/wasmJsMain/kotlin/com/example/casera/platform/ContractorSharing.wasmJs.kt

@@ -0,0 +1,11 @@
+package com.example.casera.platform
+
+import androidx.compose.runtime.Composable
+import com.example.casera.models.Contractor
+
+@Composable
+actual fun rememberShareContractor(): (Contractor) -> Unit {
+    return { _: Contractor ->
+        // Not implemented for Wasm/Web
+    }
+}