feat(editor): improve visibility of hidden content of edgeless note (#12068)

Close [BS-3066](https://linear.app/affine-design/issue/BS-3066/优化长note的展示和折叠)

- Enhanced the visibility behavior of hidden content in edgeless notes by:
  - Showing hidden content when a note is being edited, even when it's outside the viewport
  - Improving hover behavior with a delay when leaving from the bottom of the note
  - Adding proper cleanup of hover timeouts when the component is disconnected
  - Optimizing the viewport element to keep editing blocks or elements visible

## Testing
- Added new E2E test cases covering:
  - Hover behavior on selected notes
  - Content visibility during editing
  - Viewport scrolling behavior
  - Edge cases for content visibility

## Impact
This change improves the user experience when working with collapsed notes in edgeless mode by making the content more accessible and preventing accidental content hiding during editing.

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

- **Bug Fixes**
	- Improved visibility of hidden content in edgeless notes when hovering near the bottom edge or editing the note, especially after resizing or clipping.
- **New Features**
	- Enhanced hover behavior with delayed clearing based on mouse position to improve user experience.
- **Tests**
	- Added new tests verifying hidden content visibility in edgeless notes during hover and editing, simulating diverse user interactions.
- **Chores**
	- Added utilities to get and set viewport center for improved test control.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

tests/blocksuite/e2e/edgeless/note/note.spec.ts

@@ -10,10 +10,13 @@ import {
   dragBetweenViewCoords,
   getSelectedBound,
   getSelectedBoundCount,
+  getViewportCenter,
   locatorComponentToolbar,
   locatorEdgelessZoomToolButton,
+  resizeElementByHandle,
   selectNoteInEdgeless,
   setEdgelessTool,
+  setViewportCenter,
   switchEditorMode,
   triggerComponentToolbarAction,
   zoomOutByKeyboard,
@@ -34,6 +37,7 @@ import {
   pressArrowUp,
   pressBackspace,
   pressEnter,
+  pressEscape,
   pressTab,
   selectAllByKeyboard,
   type,
@@ -576,3 +580,111 @@ test('should not select doc only note', async ({ page }) => {
   );
   expect(await getSelectedBoundCount(page)).toBe(0);
 });
+
+test.describe('visibility of hidden content of edgeless note', () => {
+  test.beforeEach(async ({ page }) => {
+    await enterPlaygroundRoom(page);
+    await initEmptyEdgelessState(page);
+    await switchEditorMode(page);
+
+    const note = page.locator('affine-edgeless-note');
+    await note.click({ clickCount: 3 });
+    await type(page, 'hello');
+    await pressEnter(page, 30);
+    await type(page, 'world');
+    await pressEscape(page, 3);
+
+    const vpCenter = await getViewportCenter(page);
+    vpCenter[1] += 1000;
+    await setViewportCenter(page, vpCenter);
+
+    await note.click();
+    await resizeElementByHandle(page, { x: 0, y: -300 }, 'bottom-right');
+  });
+
+  test('should hide content when note is not selected or hovered when selected', async ({
+    page,
+  }) => {
+    const note = page.locator('affine-edgeless-note');
+    const lastParagraph = page.locator('affine-paragraph').last();
+
+    await pressEscape(page, 3);
+    await expect(lastParagraph).not.toBeInViewport();
+
+    const noteBound = await note.boundingBox();
+    if (!noteBound) {
+      test.fail();
+      return;
+    }
+    await note.click();
+    // move out to right side
+    await page.mouse.move(
+      noteBound.x + noteBound.width + 10,
+      noteBound.y + noteBound.height - 10
+    );
+    await expect(lastParagraph).not.toBeInViewport();
+  });
+
+  test('should show hidden content when hover on selected note', async ({
+    page,
+  }) => {
+    const note = page.locator('affine-edgeless-note');
+    const lastParagraph = page.locator('affine-paragraph').last();
+
+    const noteBound = await note.boundingBox();
+    if (!noteBound) {
+      test.fail();
+      return;
+    }
+
+    // move in right side
+    await page.mouse.move(
+      noteBound.x + noteBound.width - 10,
+      noteBound.y + noteBound.height - 10
+    );
+    await expect(lastParagraph).toBeInViewport();
+
+    // move to hidden content
+    await page.mouse.move(
+      noteBound.x + noteBound.width - 10,
+      noteBound.y + noteBound.height + 100
+    );
+    await expect(lastParagraph).toBeInViewport();
+  });
+
+  test('should show hidden content when the note is being edited', async ({
+    page,
+  }) => {
+    const note = page.locator('affine-edgeless-note');
+    const lastParagraph = page.locator('affine-paragraph').last();
+
+    await note.click({ clickCount: 3 });
+    await page.locator('affine-paragraph').nth(22).click();
+    await type(page, 'test');
+
+    await expect(lastParagraph).toBeInViewport();
+
+    await note.click({ clickCount: 3 });
+    await page.locator('affine-paragraph').nth(22).click();
+
+    const noteBound = await note.boundingBox();
+    if (!noteBound) {
+      test.fail();
+      return;
+    }
+    await page.mouse.move(
+      noteBound.x + noteBound.width - 10,
+      noteBound.y + noteBound.height - 10
+    );
+    await expect(lastParagraph).toBeInViewport();
+
+    await note.click({ clickCount: 3 });
+    await page.locator('affine-paragraph').nth(22).click();
+
+    await page.mouse.wheel(0, 200);
+    await expect(
+      lastParagraph,
+      'editing note but out of viewport should also show hidden content'
+    ).toBeInViewport();
+  });
+});

tests/blocksuite/e2e/utils/actions/edgeless.ts

@@ -970,6 +970,25 @@ export async function getZoomLevel(page: Page) {
   return Number(text.replace('%', ''));
 }
 
+export async function getViewportCenter(page: Page): Promise<[number, number]> {
+  return page.evaluate(() => {
+    const target = document.querySelector('affine-edgeless-root');
+    if (!target) {
+      throw new Error('Missing edgeless page');
+    }
+    return [target.gfx.viewport.centerX, target.gfx.viewport.centerY];
+  });
+}
+export async function setViewportCenter(page: Page, center: [number, number]) {
+  await page.evaluate(center => {
+    const target = document.querySelector('affine-edgeless-root');
+    if (!target) {
+      throw new Error('Missing edgeless page');
+    }
+    target.gfx.viewport.setCenter(center[0], center[1]);
+  }, center);
+}
+
 export async function optionMouseDrag(
   page: Page,
   start: number[],