Update Swift Quickstart for Ditto v5 + Swift 6 / strict-concurrency readiness

[Aaron LaBeau (biozal)]

This PR migrates the Swift quickstart from Ditto SDK 4.14.3 → 5.0.0 and brings the sample up to Swift 6 / strict-concurrency standards.

1. SDK migration (DittoSwift 4.x → 5.0.0)

Initialization — sync init → async Ditto.open

The v4 synchronous identity-based initializer is gone. v5 introduces an async config-based open.

Before (v4)	After (v5)
Ditto(identity: .onlinePlayground(appID:token:enableDittoCloudSync:customAuthURL:))	try await Ditto.open(config: DittoConfig(databaseID:connect: .server(url:)))
appID	databaseID
customAuthURL	connect: .server(url:)
enableDittoCloudSync: false	(removed — implicit)
transportConfig.connect.webSocketURLs.insert(...)	(removed — Auth URL is canonical)
try ditto.disableSyncWithV3()	(removed — v5 only)

Token refresh now uses auth.expirationHandler + auth.login

DittoManager.initDitto() registers an expiration handler that re-authenticates with auth.login(token:provider: .development) when the token nears expiry.

Sync API namespacing

Before	After
ditto.startSync()	ditto.sync.start()
ditto.stopSync()	ditto.sync.stop()
ditto.isSyncActive	ditto.sync.isActive

DQL strict mode bootstrap removed

v5 no longer requires ALTER SYSTEM SET DQL_STRICT_MODE = false for unfielded SELECTs against the quickstart schema, so TasksApp.task now just calls
DittoManager.shared.initDitto().

Package dependency

• DittoSwiftPackage bumped to 5.0.0 (upToNextMinor).
• DittoObjC product dependency dropped — DittoSwift now ships its ObjC bridge internally.

2. Concurrency / Swift 6 strict-concurrency

The PR-review feedback flagged a real data-race bug in the initial v5 port (@Published ditto mutated from a non-MainActor continuation). Audit found and fixed several related
issues so the sample is Swift 6 strict-concurrency clean and a faithful reference for SDK consumers.

#	Issue	Fix
1	DittoManager not @MainActor — self.ditto = ... after await Ditto.open(...) could resume off-main and publish from a background thread.	Annotated @MainActor on DittoManager.
2	EditScreenViewModel not @MainActor despite owning four @Published properties.	Annotated @MainActor.
3	Five Task {} blocks in TasksListScreenViewModel captured self strongly; four were on nonisolated methods — Swift 6 sending self errors and unbounded VM lifetime.	All five blocks now [weak self] + guard let self; nonisolated removed from saveEditedTask, saveNewTask, deleteTask, populateTasksCollection (all are called only from @MainActor SwiftUI contexts).
4	deinit accessed @MainActor-isolated subscription, storeObserver, ditto — deinit is always nonisolated, so this was a Swift 6 isolation violation.	Cleanup moved into @MainActor func teardown(), invoked from .onDisappear.
5	private let ditto = DittoManager.shared.ditto captured the optional at init time — if the VM ever initialized before initDitto() finished it would silently capture nil forever.	Replaced with private var ditto: Ditto? { DittoManager.shared.ditto } (computed).
6	TaskModel had only implicit Sendable synthesis despite crossing actor boundaries.	Explicit struct TaskModel: Sendable.
7	Stale UserDefaults.standard.synchronize() call (no-op since iOS 12).	Removed.

Observer callback was already correct

The DittoStoreObserver callback in init() already hops back to MainActor via Task { @MainActor [weak self] in self?.tasks = mappedTasks } — preserved unchanged.

3. Project / housekeeping

• LastUpgradeCheck bumped (1610 → 2620).
• Dev team setting removed for cross-account portability.
• Added LSApplicationCategoryType = public.app-category.developer-tools.
• STRING_CATALOG_GENERATE_SYMBOLS = YES for both build configs.
• Toolbar refactor: ToolbarItem → ToolbarItemGroup; HStack { Image; Text } → Label("New Task", systemImage: "plus").

4. README

• Xcode requirement: 15 → 16+ (Swift 6).
• API reference link: 4.8.2 → 5.0.0.
• "App ID" terminology updated to Database ID (with note that it was previously called App ID).
• Removed reference to DITTO_WEBSOCKET_URL in setup steps (Auth URL covers it in v5).

Test plan

• Build succeeds in Xcode 16+ with strict-concurrency = complete.
• Cold launch shows ProgressView, then TasksListScreen once initDitto() resolves.
• Initial four seed tasks appear (Buy groceries / Clean the kitchen / Schedule dentist / Pay bills).
• Toggle a task's "done" → persists across relaunch.
• Create / edit / delete tasks via EditScreen — all CRUD paths work.
• Toggle Sync off/on — ditto.sync.isActive reflects state; subscription is cancelled/recreated.
• Two devices on the same Database ID sync tasks bidirectionally.
• Background → foreground after token TTL: auth.expirationHandler re-auths without crash.
• Navigate away from TasksListScreen → teardown() runs (observers cancelled, sync stopped).
• No purple "Publishing changes from background threads" runtime warnings.

[Copilot]

Pull request overview

Updates the Swift Tasks quickstart to use DittoSwift v5 APIs and project settings, aligning the sample app’s initialization/sync flows and documentation with the upcoming major release.

Changes:

• Migrates Ditto initialization and sync calls to the v5 API surface (new DittoConfig/Ditto.open, ditto.sync.*).
• Updates Xcode project/SwiftPM dependency to DittoSwiftPackage 5.0.0 and adjusts UI toolbar layout.
• Refreshes the Swift quickstart README links and setup instructions for v5 terminology.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
swift/Tasks/TasksListScreen.swift	Updates observer/sync usage for v5 and tweaks toolbar UI (Toggle label / bottom bar button).
swift/Tasks/TasksApp.swift	Switches startup to async Ditto initialization via DittoManager.initDitto().
swift/Tasks/TaskModel.swift	Adds Foundation import (for Data, UUID, etc.).
swift/Tasks/DittoManager.swift	Reworks Ditto lifecycle to async open + auth refresh handler; makes ditto optional/published.
swift/Tasks.xcodeproj/xcshareddata/xcschemes/Tasks.xcscheme	Updates scheme metadata (upgrade version).
swift/Tasks.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved	Pins DittoSwiftPackage to 5.0.0.
swift/Tasks.xcodeproj/project.pbxproj	Removes DittoObjC linkage, updates package requirement, and updates build settings.
swift/README.md	Updates prerequisites, API reference link, and setup steps for v5 terms.

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[Skyler Jokiel (skylerjokiel)]

🚀

[John Cunningham (SausCode)]

Looks good overall, approved with a few nits