GUI: Weggezogen-Bug (stale detail poll) gefixt + Redesign mit Dark/Light-Switch

- Detail-Poll bricht bei Auswahlwechsel ab, pollt nur Status, EIN Rebuild
  bei Fertigstellung mit Player-Restore
- Themes via CSS-Variablen (data-theme, localStorage, OS-Default),
  Kupfer-Akzent, Wellenform-Wortmarke, Pill-Tabs, focus-visible,
  prefers-reduced-motion

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0113vDKdSNtD3Dwcw4QMu9yV

app/web/index.html

@@ -4,6 +4,15 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <title>Aime</title>
+    <script>
+      // Theme before first paint (no flash): saved choice wins, else OS setting.
+      (function () {
+        var t = localStorage.getItem('aime-theme');
+        if (t !== 'light' && t !== 'dark')
+          t = matchMedia('(prefers-color-scheme: light)').matches ? 'light' : 'dark';
+        document.documentElement.dataset.theme = t;
+      })();
+    </script>
   </head>
   <body>
     <div id="app"></div>