fix(ios): stabilize keyboard toolbar, image picker, and scrolling (#15182)

## Summary
- keep the editor active when iOS keyboard toolbar interactions move
focus into range-sync excluded widgets
- use the native iOS image picker/source sheet and sync native
presentation with the app theme
- pin `ListViewKit` to `1.1.6` so the iOS workspace resolves with Xcode
16.3
- restore vertical scrolling in the iOS `WKWebView` by removing the
global `contentOffset` reset while preserving zoom prevention

## Test plan
- [x] `yarn vitest --run --config \"vitest.config.ts\"
--browser.enabled=false \"src/__tests__/inline/active.unit.spec.ts\"`
- [x] `LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8 xcodebuild
-resolvePackageDependencies -workspace
\"packages/frontend/apps/ios/App/App.xcworkspace\" -scheme \"App\"`
- [x] `xcodebuild -workspace \"App.xcworkspace\" -scheme \"App\"
-destination \"generic/platform=iOS Simulator\" build
CODE_SIGNING_ALLOWED=NO ONLY_ACTIVE_ARCH=YES ARCHS=arm64`
- [x] Xcode build validation for the updated PR branch

blocksuite/framework/std/src/__tests__/inline/active.unit.spec.ts

@@ -0,0 +1,66 @@
+/**
+ * @vitest-environment happy-dom
+ */
+import { afterEach, describe, expect, test } from 'vitest';
+
+import { shouldDeactivateEditorOnFocusOut } from '../../inline/range/active.js';
+import { RANGE_SYNC_EXCLUDE_ATTR } from '../../inline/range/consts.js';
+
+afterEach(() => {
+  document.body.replaceChildren();
+});
+
+describe('editor active helpers', () => {
+  test('keeps editor active when focus moves into an excluded widget', () => {
+    const host = document.createElement('editor-host');
+    const paragraph = document.createElement('div');
+    host.append(paragraph);
+
+    const widgetRoot = document.createElement('div');
+    widgetRoot.setAttribute(RANGE_SYNC_EXCLUDE_ATTR, 'true');
+    const widgetButton = document.createElement('button');
+    widgetRoot.append(widgetButton);
+
+    document.body.append(host, widgetRoot);
+
+    expect(shouldDeactivateEditorOnFocusOut(host, widgetButton)).toBe(false);
+  });
+
+  test('keeps editor active when focus stays inside the editor host', () => {
+    const host = document.createElement('editor-host');
+    const input = document.createElement('input');
+    host.append(input);
+    document.body.append(host);
+
+    expect(shouldDeactivateEditorOnFocusOut(host, input)).toBe(false);
+  });
+
+  test('deactivates editor when focus moves to a regular external control', () => {
+    const host = document.createElement('editor-host');
+    const paragraph = document.createElement('div');
+    host.append(paragraph);
+
+    const externalButton = document.createElement('button');
+    document.body.append(host, externalButton);
+
+    expect(shouldDeactivateEditorOnFocusOut(host, externalButton)).toBe(true);
+  });
+
+  test('keeps editor active on focusout when related target is null', () => {
+    // Focus leaving to nowhere (e.g. block-level selection) must not deactivate
+    // the editor via `focusout`; the host `blur` handler owns that case.
+    const host = document.createElement('editor-host');
+    document.body.append(host);
+
+    expect(shouldDeactivateEditorOnFocusOut(host, null)).toBe(false);
+  });
+
+  test('keeps editor active when the related target is not a DOM node', () => {
+    const host = document.createElement('editor-host');
+    document.body.append(host);
+
+    expect(shouldDeactivateEditorOnFocusOut(host, new EventTarget())).toBe(
+      false
+    );
+  });
+});