fix(editor): chat cannot scroll on windows (#14677)

fix #14529 
fix #14612 
replace #14614 #14657


#### PR Dependency Tree


* **PR #14677** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Tests**
* Added test coverage for scroll position tracking and pinned scroll
behavior in AI chat
* Added test suite verifying scroll-to-end and scroll-to-position
functionality

* **New Features**
* Introduced configurable scrollable option for text rendering in AI
chat components, allowing control over scroll behavior

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/core/src/blocksuite/ai/components/ai-chat-content/ai-chat-content.spec.ts

@@ -0,0 +1,41 @@
+/**
+ * @vitest-environment happy-dom
+ */
+import { describe, expect, test, vi } from 'vitest';
+
+import { AIChatContent } from './ai-chat-content';
+
+describe('AIChatContent pinned scroll tracking', () => {
+  test('records scroll position from the chat messages host', async () => {
+    let scrollEndHandler: (() => void) | undefined;
+
+    const chatMessages = {
+      scrollTop: 256,
+      updateComplete: Promise.resolve(),
+      addEventListener: vi.fn((event: string, handler: EventListener) => {
+        if (event === 'scrollend') {
+          scrollEndHandler = handler as () => void;
+        }
+      }),
+    };
+
+    const content = {
+      chatMessagesRef: { value: chatMessages },
+      _scrollListenersInitialized: false,
+      lastScrollTop: undefined,
+    } as unknown as AIChatContent;
+
+    (AIChatContent.prototype as any)._initializeScrollListeners.call(content);
+    await chatMessages.updateComplete;
+    await Promise.resolve();
+
+    expect(chatMessages.addEventListener).toHaveBeenCalledWith(
+      'scrollend',
+      expect.any(Function)
+    );
+
+    scrollEndHandler?.();
+
+    expect((content as any).lastScrollTop).toBe(256);
+  });
+});

packages/frontend/core/src/blocksuite/ai/components/ai-chat-messages/ai-chat-messages.spec.ts

@@ -0,0 +1,50 @@
+/**
+ * @vitest-environment happy-dom
+ */
+import { afterEach, beforeEach, describe, expect, test, vi } from 'vitest';
+
+import { AIChatMessages } from './ai-chat-messages';
+
+describe('AIChatMessages scrolling', () => {
+  beforeEach(() => {
+    vi.stubGlobal('requestAnimationFrame', (cb: FrameRequestCallback) => {
+      cb(0);
+      return 1;
+    });
+  });
+
+  afterEach(() => {
+    vi.unstubAllGlobals();
+    vi.restoreAllMocks();
+  });
+
+  test('scrollToEnd scrolls the host element', () => {
+    const scrollTo = vi.fn();
+    const element = {
+      scrollTo,
+    } as unknown as AIChatMessages;
+
+    Object.defineProperty(element, 'scrollHeight', {
+      configurable: true,
+      value: 480,
+    });
+
+    AIChatMessages.prototype.scrollToEnd.call(element);
+
+    expect(scrollTo).toHaveBeenCalledWith({
+      top: 480,
+      behavior: 'smooth',
+    });
+  });
+
+  test('scrollToPos scrolls the host element', () => {
+    const scrollTo = vi.fn();
+    const element = {
+      scrollTo,
+    } as unknown as AIChatMessages;
+
+    AIChatMessages.prototype.scrollToPos.call(element, 128);
+
+    expect(scrollTo).toHaveBeenCalledWith({ top: 128 });
+  });
+});

packages/frontend/core/src/blocksuite/ai/components/ai-message-content/rich-text.ts

@@ -32,6 +32,7 @@ export class ChatContentRichText extends WithDisposable(ShadowlessElement) {
       extensions: this.extensions,
       affineFeatureFlagService: this.affineFeatureFlagService,
       theme: this.theme,
+      scrollable: false,
     })(text, this.state)}`;
   }
 }

packages/frontend/core/src/blocksuite/ai/components/text-renderer.ts

@@ -85,6 +85,7 @@ export type TextRendererOptions = {
   testId?: string;
   affineFeatureFlagService?: FeatureFlagService;
   theme?: Signal<ColorScheme>;
+  scrollable?: boolean;
 };
 
 // todo: refactor it for more general purpose usage instead of AI only?
@@ -140,9 +141,12 @@ export class TextRenderer extends SignalWatcher(
     }
 
     .text-renderer-container {
+      padding: 0;
+    }
+
+    .text-renderer-container.scrollable {
       overflow-y: auto;
       overflow-x: hidden;
-      padding: 0;
       overscroll-behavior-y: none;
     }
     .text-renderer-container.show-scrollbar::-webkit-scrollbar {
@@ -325,6 +329,7 @@ export class TextRenderer extends SignalWatcher(
     const classes = classMap({
       'text-renderer-container': true,
       'custom-heading': !!customHeading,
+      scrollable: this.options.scrollable !== false,
     });
     const theme = this.options.theme?.value;
     return html`