Convert frontend code to typescript (#31559)

None of the frontend js/ts files was touched besides these two commands
(edit: no longer true, I touched one file in
61105d0618
because of a deprecation that was not showing before the rename).

`tsc` currently reports 778 errors, so I have disabled it in CI as
planned.

Everything appears to work fine.

web_src/js/features/repo-commit.ts

@@ -0,0 +1,27 @@
+import {createTippy} from '../modules/tippy.ts';
+import {toggleElem} from '../utils/dom.ts';
+
+export function initRepoEllipsisButton() {
+  for (const button of document.querySelectorAll('.js-toggle-commit-body')) {
+    button.addEventListener('click', function (e) {
+      e.preventDefault();
+      const expanded = this.getAttribute('aria-expanded') === 'true';
+      toggleElem(this.parentElement.querySelector('.commit-body'));
+      this.setAttribute('aria-expanded', String(!expanded));
+    });
+  }
+}
+
+export function initCommitStatuses() {
+  for (const element of document.querySelectorAll('[data-tippy="commit-statuses"]')) {
+    const top = document.querySelector('.repository.file.list') || document.querySelector('.repository.diff');
+
+    createTippy(element, {
+      content: element.nextElementSibling,
+      placement: top ? 'top-start' : 'bottom-start',
+      interactive: true,
+      role: 'dialog',
+      theme: 'box-with-header',
+    });
+  }
+}