fix: SyntaxHighlighter crashes on background queue due to implicit MainActor isolation

[batonogov]

Summary

Pine crashes immediately on launch when opening a file. SyntaxHighlighter.resolveGrammar(language:fileName:) is called on the background com.pine.syntax-highlight serial queue, but Swift runtime asserts MainActor isolation and triggers dispatch_assert_queue_fail → SIGTRAP.

Crash Stack

Thread 1 Crashed:: Dispatch queue: com.pine.syntax-highlight (QOS: USER_INITIATED)
_dispatch_assert_queue_fail
dispatch_assert_queue
_swift_task_checkIsolatedSwift
swift_task_isCurrentExecutorWithFlagsImpl
closure #1 in SyntaxHighlighter.resolveGrammar(language:fileName:) (SyntaxHighlighter.swift:500)
SyntaxHighlighter.resolveGrammar(language:fileName:) (SyntaxHighlighter.swift:500)
SyntaxHighlighter.computeMatches (SyntaxHighlighter.swift:674)
SyntaxHighlighter.highlightAsync (SyntaxHighlighter.swift:802)

Root Cause

SWIFT_DEFAULT_ACTOR_ISOLATION = MainActor in build settings makes SyntaxHighlighter (a class) implicitly @MainActor. But highlightAsync dispatches work to a background serial queue (com.pine.syntax-highlight), and resolveGrammar accesses @MainActor-isolated state from that queue. Swift runtime detects the violation and crashes.

Motivation

App crashes on launch — completely blocks usage.

Implementation ideas

• Mark SyntaxHighlighter as nonisolated (it manages its own thread safety via NSLock + serial queue)
• Or mark specific methods/closures as nonisolated / @Sendable
• Same pattern may affect other classes that do background work: GitStatusProvider, ProjectSearchProvider, WorkspaceManager
• Audit all classes that dispatch to background queues

[batonogov]

Второй краш — FileNode

Тот же паттерн: FileNode.init(url:context:depth:) вызывается из WorkspaceManager.loadDirectoryContentsAsync на background DispatchQueue.global(), но FileNode (@observable class) стал неявно @MainActor.

Thread 12 Crashed:: com.apple.root.user-initiated-qos
dispatch_assert_queue_fail → _swift_task_checkIsolatedSwift
→ FileNode.init (FileNode.swift:62)
→ FileNode.loadTree (FileNode.swift:176)
→ WorkspaceManager.loadDirectoryContentsAsync (WorkspaceManager.swift:156)

Нужно пометить FileNode как nonisolated или убрать из него @Observable в контексте background init.

Затронутые классы для аудита:

• SyntaxHighlighter — краш в resolveGrammar ✓
• FileNode — краш в init ✓
• WorkspaceManager — dispatches to background
• GitStatusProvider — dispatches to background
• ProjectSearchProvider — uses TaskGroup
• FileSystemWatcher — background callback

[batonogov]

Третий краш — PreviewItem

@objc PreviewItem.previewItemURL.getter вызывается QuickLook на background queue. PreviewItem нужен nonisolated.

Thread 10 снова FileNode.init — подтверждение что FileNode fix обязателен.