refactor(web): 前端目录重构 — consoles/pages → layouts/features + shared

- consoles/admin/ → layouts/admin-layout/
- consoles/workbench/ → layouts/workbench-layout/ + features/chat/
- pages/ → features/ (dashboard, models, projects, not-found)
- components/ → shared/components/
- hooks/ → shared/hooks/
- utils/ → shared/utils/
- 更新所有 import 路径 (src/web/ + tests/web/)
- 更新开发文档 (README.md, frontend.md, architecture.md)

tests/web/hooks/use-theme-preference.test.ts

@@ -8,7 +8,7 @@ import {
   THEME_MEDIA_QUERY,
   THEME_PREFERENCE_STORAGE_KEY,
   writeThemePreference,
-} from "../../../src/web/hooks/use-theme-preference";
+} from "../../../src/web/shared/hooks/use-theme-preference";
 
 function createStorage(initial?: string): Storage {
   const values = new Map<string, string>();