fix: improve AI Assist input visibility and use valid Qwen models

- Added text-slate-100 dark:text-slate-100 to input for visible text on dark bg
- Updated Qwen models to use valid names: qwen-coder-plus, qwen-turbo, etc
- Set qwen-coder-plus as default model for best coding assistance

components/AIAssist.tsx

@@ -645,7 +645,7 @@ export default function AIAssist() {
                                 onChange={(e) => setInput(e.target.value)}
                                 placeholder={t.placeholder}
                                 disabled={isProcessing}
-                                className="relative pr-24 py-7 rounded-[1.5rem] bg-white/90 dark:bg-[#0f1a1a]/70 border-blue-200/80 dark:border-blue-900/80 shadow-lg shadow-blue-500/5 focus:ring-4 focus:ring-blue-500/10 transition-all font-medium text-base h-16 outline-none"
+                                className="relative pr-24 py-7 rounded-[1.5rem] bg-white/90 dark:bg-[#0f1a1a]/70 border-blue-200/80 dark:border-blue-900/80 shadow-lg shadow-blue-500/5 focus:ring-4 focus:ring-blue-500/10 transition-all font-medium text-base h-16 outline-none text-slate-900 dark:text-slate-100 placeholder:text-slate-400 dark:placeholder:text-slate-500"
                             />
                             <div className="absolute right-3 top-1/2 -translate-y-1/2 flex items-center gap-2">
                                 {isProcessing ? (

lib/services/qwen-oauth.ts

@@ -1116,7 +1116,11 @@ Perform analysis based on provided instructions.`,
 
   getAvailableModels(): string[] {
     return [
-      "coder-model",
+      "qwen-coder-plus",
+      "qwen-plus",
+      "qwen-turbo",
+      "qwen-max",
+      "qwen-coder-turbo",
     ];
   }
 }

lib/store.ts

@@ -64,12 +64,12 @@ const useStore = create<AppState>((set) => ({
   language: "en",
   selectedProvider: "qwen",
   selectedModels: {
-    qwen: "coder-model",
+    qwen: "qwen-coder-plus",
     ollama: "gpt-oss:120b",
     zai: "glm-4.7",
   },
   availableModels: {
-    qwen: ["coder-model"],
+    qwen: ["qwen-coder-plus", "qwen-plus", "qwen-turbo", "qwen-max", "qwen-coder-turbo"],
     ollama: ["gpt-oss:120b", "llama3.1", "gemma3", "deepseek-r1", "qwen3"],
     zai: ["glm-4.7", "glm-4.6", "glm-4.5", "glm-4.5-air", "glm-4-flash", "glm-4-flashx"],
   },