feat(repo): add quick repository switcher to repo header (#38188)

Add a GitHub-style quick repo switcher: a caret next to the owner/repo
breadcrumb
opens a dropdown that lists and searches the current owner's
repositories and
navigates to the selected one. The current repository is marked with a
check, and
private/fork repos show an icon.

Also, fix various bugs in fomtantic dropdown remote query

## Screenshots

<img width="505" height="198" alt="image"
src="https://github.com/user-attachments/assets/9f673d1b-fe60-41f0-b9e2-b00dc43720b5"
/>

Fixes #38187

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/js/features/common-page.ts

@@ -6,6 +6,7 @@ import {addDelegatedEventListener, queryElems} from '../utils/dom.ts';
 import {registerGlobalInitFunc, registerGlobalSelectorFunc} from '../modules/observer.ts';
 import {initAvatarUploaderWithCropper} from './comp/Cropper.ts';
 import {initCompSearchRepoBox} from './comp/SearchRepoBox.ts';
+import {initRepoSwitcher} from './repo-switcher.ts';
 import {initScopedWorkflowRequired} from './comp/ScopedWorkflows.ts';
 
 const {appUrl, appSubUrl} = window.config;
@@ -38,7 +39,7 @@ function initFooterThemeSelector() {
   const $dropdown = fomanticQuery(elDropdown);
   $dropdown.dropdown({
     direction: 'upward',
-    apiSettings: {url: `${appSubUrl}/-/web-theme/list`, cache: false},
+    apiSettings: {url: `${appSubUrl}/-/web-theme/list`},
   });
   addDelegatedEventListener(elDropdown, 'click', '.menu > .item', async (el) => {
     const themeName = el.getAttribute('data-value')!;
@@ -105,6 +106,7 @@ export function initGlobalComponent() {
   registerGlobalInitFunc('initTabSwitcher', initTabSwitcher);
   registerGlobalInitFunc('initAvatarUploader', initAvatarUploaderWithCropper);
   registerGlobalInitFunc('initSearchRepoBox', initCompSearchRepoBox);
+  registerGlobalInitFunc('initRepoSwitcher', initRepoSwitcher);
   registerGlobalInitFunc('initScopedWorkflowRequired', initScopedWorkflowRequired);
 }