feat: Implement features and continuously optimize the proxy service

- Settings page UI
- Persist settings data
- Proxy server fixes & optimizations:
  - Fixed download latency caused by Range Seek
  - Improved cache stability
  - Implemented a dual-threading model to ensure smooth playback
- Optimized styles for the homepage TopBar and SideBar
- Added theme switching functionality
- Added theme color customization feature

src/renderer/App.vue

@@ -1,9 +1,26 @@
 <template>
   <MainLayout />
+  <Settings v-if="showSettings" @close="showSettings = false" />
 </template>
 
 <script setup lang="ts">
+import { ref, provide, onMounted } from 'vue';
 import MainLayout from './layout/MainLayout.vue';
+import Settings from './components/Settings.vue';
+
+const showSettings = ref(false);
+
+// Provide to child components
+provide('openSettings', () => { showSettings.value = true; });
+
+// Apply saved theme on app startup
+onMounted(async () => {
+  if (window.electronAPI?.settings) {
+    const settings = await window.electronAPI.settings.getAll();
+    document.documentElement.setAttribute('data-theme', settings.theme);
+    document.documentElement.style.setProperty('--color-accent', settings.accentColor);
+  }
+});
 </script>
 
 <style>