refactor!: remove redundant compatibility layers

Use native browser and Tauri behavior instead of custom selector, dialog, and window-state implementations. Remove obsolete bridge, relay, asset, and dependency paths to keep the supported surface small.

BREAKING CHANGE: The Noctalia relay no longer accepts --agent, and the Tauri host no longer exposes the legacy load_agent command.

ui/index.html

@@ -2,9 +2,8 @@
 <html lang="en">
   <head>
     <meta charset="UTF-8" />
-    <link rel="icon" type="image/svg+xml" href="/vite.svg" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-    <title>Tauri + React + Typescript</title>
+    <title>Pi Status UI</title>
   </head>
 
   <body>