Fix isolated deinit crashes in Markdown rendering helpers

Sources/MarkdownView/MarkdownTextBuilder/ListProcessor.swift

@@ -15,6 +15,9 @@ import MarkdownParser
 // MARK: - ListProcessor
 
 final class ListProcessor {
+    // Synchronous rendering must avoid the isolated-deinit back-deployment path.
+    nonisolated deinit {}
+
     private let theme: MarkdownTheme
     private let context: MarkdownTextView.PreprocessedContent
     private let viewProvider: ReusableViewProvider

Sources/MarkdownView/Supplements/InlineNode+Render.swift

@@ -18,6 +18,9 @@ import SwiftMath
 /// Cached attribute dictionaries to avoid repeated allocations.
 /// Keyed by theme identity (font + color) which changes infrequently.
 final class InlineAttributeCache {
+    // Synchronous rendering must avoid the isolated-deinit back-deployment path.
+    nonisolated deinit {}
+
     let bodyAttributes: [NSAttributedString.Key: Any]
     let codeAttributes: [NSAttributedString.Key: Any]
 

Tests/MarkdownViewTests/RenderingLifetimeTests.swift

@@ -0,0 +1,49 @@
+import Foundation
+import XCTest
+@testable import MarkdownView
+
+@MainActor
+final class RenderingLifetimeTests: XCTestCase {
+    private enum LayoutContext {
+        @TaskLocal static var value = "outside"
+    }
+
+    func testInlineAttributeCacheReleaseInsideSynchronousTaskLocalScope() {
+        checkSynchronousRelease {
+            InlineAttributeCache(theme: .default)
+        }
+    }
+
+    func testListProcessorAndOwnedCacheReleaseInsideSynchronousTaskLocalScope() {
+        let theme = MarkdownTheme.default
+        let context = MarkdownTextView.PreprocessedContent(markdown: "- **First**\n- `Second`", theme: theme)
+        let viewProvider = ReusableViewProvider()
+        checkSynchronousRelease {
+            ListProcessor(
+                theme: theme,
+                viewProvider: viewProvider,
+                context: context,
+                bulletDrawing: nil,
+                numberedDrawing: nil,
+                checkboxDrawing: nil
+            )
+        }
+    }
+
+    // Keep this synchronous to match UIKit layout callbacks outside a Swift task.
+    private func checkSynchronousRelease<T: AnyObject>(_ makeObject: () -> T) {
+        for _ in 0 ..< 100 {
+            LayoutContext.$value.withValue("layout") {
+                autoreleasepool {
+                    var objects = [0: makeObject()]
+                    weak var object: T?
+                    object = objects[0]
+                    objects.removeAll()
+                    XCTAssertNil(object)
+                }
+                XCTAssertEqual(LayoutContext.value, "layout")
+            }
+            XCTAssertEqual(LayoutContext.value, "outside")
+        }
+    }
+}