Fix repo home file list (#32788)

1. use grid instead of table, completely drop "ui table" from that list
2. move some "commit sign" related styles into a new file by the way (no
change) because I need to figure out where `#repo-files-table` is used.
3. move legacy "branch/tag selector" related code into repo-legacy.ts,
now there are 13 `import $` files left.

web_src/js/features/repo-legacy.ts

@@ -8,9 +8,7 @@ import {
 } from './repo-issue.ts';
 import {initUnicodeEscapeButton} from './repo-unicode-escape.ts';
 import {initRepoBranchTagSelector} from '../components/RepoBranchTagSelector.vue';
-import {
-  initRepoCloneButtons, initRepoCommonBranchOrTagDropdown, initRepoCommonFilterSearchDropdown,
-} from './repo-common.ts';
+import {initRepoCloneButtons} from './repo-common.ts';
 import {initCitationFileCopyContent} from './citation.ts';
 import {initCompLabelEdit} from './comp/LabelEdit.ts';
 import {initRepoDiffConversationNav} from './repo-diff.ts';
@@ -36,6 +34,33 @@ export function initBranchSelectorTabs() {
   });
 }
 
+function initRepoCommonBranchOrTagDropdown(selector: string) {
+  $(selector).each(function () {
+    const $dropdown = $(this);
+    $dropdown.find('.reference.column').on('click', function () {
+      hideElem($dropdown.find('.scrolling.reference-list-menu'));
+      showElem($($(this).data('target')));
+      return false;
+    });
+  });
+}
+
+function initRepoCommonFilterSearchDropdown(selector: string) {
+  const $dropdown = $(selector);
+  if (!$dropdown.length) return;
+
+  $dropdown.dropdown({
+    fullTextSearch: 'exact',
+    selectOnKeydown: false,
+    onChange(_text, _value, $choice) {
+      if ($choice[0].getAttribute('data-url')) {
+        window.location.href = $choice[0].getAttribute('data-url');
+      }
+    },
+    message: {noResults: $dropdown[0].getAttribute('data-no-results')},
+  });
+}
+
 export function initRepository() {
   if (!$('.page-content.repository').length) return;