fix(styles): fix design module style issues

[bytemain]

Types

• 🐛 Bug Fixes
• 💄 Style Changes

Background or solution

close: #3562

1. 解耦和 design 模块和 ai-native 模块有关 layout 的地方
2. design 模块右上角支持注册 component
3. e2e 模式使用默认 layout

样式优化：

1. 鼠标悬浮到 scrollbar 上自动变成 width: 10px
2. 加速插件 apply style sheet

Changelog

[railway-app]

This PR is being deployed to Railway 🚅

core: ◻️ REMOVED

[codecov]

Codecov Report

Attention: Patch coverage is 55.86854% with 94 lines in your changes are missing coverage. Please review.

Project coverage is 56.01%. Comparing base (a46c90a) to head (2e0a1ae).
Report is 2 commits behind head on main.

Files	Patch %	Lines
...s/ai-native/src/browser/light-bulb-widget/index.ts	0.00%	21 Missing and 6 partials ⚠️
packages/theme/src/browser/style.service.ts	9.52%	17 Missing and 2 partials ⚠️
packages/core-browser/src/layout/constants.ts	57.14%	12 Missing and 3 partials ⚠️
...es/editor/src/browser/editor.decoration.service.ts	76.47%	8 Missing ⚠️
packages/core-browser/src/dom/event.ts	16.66%	4 Missing and 1 partial ⚠️
...ages/ai-native/src/browser/layout/layout-config.ts	0.00%	4 Missing ⚠️
...collaboration/src/browser/collaboration.service.ts	33.33%	4 Missing ⚠️
...ackages/design/src/browser/layout/layout-config.ts	0.00%	3 Missing ⚠️
packages/design/src/browser/index.ts	0.00%	2 Missing ⚠️
packages/theme/src/common/css-var.ts	86.66%	2 Missing ⚠️
... and 5 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3586      +/-   ##
==========================================
- Coverage   56.01%   56.01%   -0.01%     
==========================================
  Files        1490     1503      +13     
  Lines       91318    91459     +141     
  Branches    18736    18747      +11     
==========================================
+ Hits        51152    51228      +76     
- Misses      33305    33360      +55     
- Partials     6861     6871      +10     

Flag	Coverage Δ
jsdom	51.42% <55.86%> (+<0.01%)	⬆️
node	15.64% <21.12%> (+0.01%)	⬆️

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