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/components/ping.ts

@@ -60,7 +60,7 @@ const component: ClosureComponent = (vn): Component => {
         }
       }
 
-      return m("div", host ? `Pinging ${host}:` : "");
+      return m("div.text-sm my-4", host ? `Pinging ${host}:` : "");
     },
   };
 };