Implement unified network layer with APILayer and migrate iOS ViewModels

Major architectural improvements:
- Created APILayer as single entry point for all network operations
- Integrated cache-first reads with automatic cache updates on mutations
- Migrated all shared Kotlin ViewModels to use APILayer instead of direct API calls
- Migrated iOS ViewModels to wrap shared Kotlin ViewModels with StateFlow observation
- Replaced LookupsManager with DataCache for centralized lookup data management
- Added password reset methods to AuthViewModel
- Added task completion and update methods to APILayer
- Added residence user management methods to APILayer

iOS specific changes:
- Updated LoginViewModel, RegisterViewModel, ProfileViewModel to use shared AuthViewModel
- Updated ContractorViewModel, DocumentViewModel to use shared ViewModels
- Updated ResidenceViewModel to use shared ViewModel and APILayer
- Updated TaskViewModel to wrap shared ViewModel with callback-based interface
- Migrated PasswordResetViewModel and VerifyEmailViewModel to shared AuthViewModel
- Migrated AllTasksView, CompleteTaskView, EditTaskView to use APILayer
- Migrated ManageUsersView, ResidenceDetailView to use APILayer
- Migrated JoinResidenceView to use async/await pattern with APILayer
- Removed LookupsManager.swift in favor of DataCache
- Fixed PushNotificationManager @MainActor issue
- Converted all direct API calls to use async/await with proper error handling

Benefits:
- Reduced code duplication between iOS and Android
- Consistent error handling across platforms
- Automatic cache management for better performance
- Centralized network layer for easier testing and maintenance
- Net reduction of ~700 lines of code through shared logic

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

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

composeApp/build.gradle.kts

@@ -11,6 +11,7 @@ plugins {
     alias(libs.plugins.composeHotReload)
     alias(libs.plugins.kotlinxSerialization)
     alias(libs.plugins.googleServices)
+    id("co.touchlab.skie") version "0.10.7"
 }
 
 kotlin {
@@ -83,7 +84,6 @@ kotlin {
             implementation(libs.kotlinx.datetime)
             implementation(libs.ktor.client.logging)
             implementation(compose.materialIconsExtended)
-            implementation("org.jetbrains.kotlinx:kotlinx-datetime:<latest-version>")
             implementation(libs.coil.compose)
             implementation(libs.coil.network.ktor3)
         }