feat(ui): redesign UI with Tailwind CSS, CodeMirror 6, and new layout

- Replace all hand-written CSS with Tailwind utility classes
- Upgrade CodeMirror 5 to CodeMirror 6 (scoped @codemirror/* packages)
- Redesign layout with responsive sidebar navigation using JSX/Mithril
- Flatten admin routes (e.g. /admin/presets -> /presets)
- Add "remember me" login option with 2-week persistent cookie
- Add delete confirmation dialogs across admin pages
- Upgrade esbuild from 0.21 to 0.27 and update browser targets
- Add Inter and Roboto Mono variable fonts with subset script

ui/store.ts

@@ -657,12 +657,16 @@ export function changePassword(
   });
 }
 
-export function logIn(username: string, password: string): Promise<void> {
+export function logIn(
+  username: string,
+  password: string,
+  remember = false,
+): Promise<void> {
   return xhrRequest({
     method: "POST",
     url: "login",
     background: true,
-    body: { username, password },
+    body: { username, password, remember },
   });
 }