refactor(models): enhance model management with official provider marking and extended metadata

- Add OFFICIAL_PROVIDERS set to mark first-party vendors in models.dev
- Implement official provider marking function with cache compatibility
- Extend model metadata with family, context_limit, output_limit fields
- Improve frontend model selection UI with wider panel and better search
- Add dark mode support for provider logos
- Optimize scrollbar styling for model lists
- Update deployment documentation with clearer migration steps

frontend/src/style.css

@@ -1169,4 +1169,26 @@ body[theme-mode='dark'] .literary-annotation {
   .scrollbar-hide::-webkit-scrollbar {
     display: none;
   }
-}
+
+  .scrollbar-thin {
+    scrollbar-width: thin;
+    scrollbar-color: hsl(var(--border)) transparent;
+  }
+
+  .scrollbar-thin::-webkit-scrollbar {
+    width: 6px;
+  }
+
+  .scrollbar-thin::-webkit-scrollbar-track {
+    background: transparent;
+  }
+
+  .scrollbar-thin::-webkit-scrollbar-thumb {
+    background-color: hsl(var(--border));
+    border-radius: 3px;
+  }
+
+  .scrollbar-thin::-webkit-scrollbar-thumb:hover {
+    background-color: hsl(var(--muted-foreground) / 0.5);
+  }
+}