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/models/Residence.kt

@@ -232,13 +232,9 @@ data class ResidenceTaskSummary(
 )
 
 /**
- * Residence users response
+ * Residence users response - API returns a flat list of all users with access
  */
-@Serializable
-data class ResidenceUsersResponse(
-    val owner: ResidenceUserResponse,
-    val users: List<ResidenceUserResponse>
-)
+typealias ResidenceUsersResponse = List<ResidenceUserResponse>
 
 /**
  * Remove user response