fix(providers): remove Qwen provider support

Qwen OAuth flow (portal.qwen.ai) stopped working reliably; drop the
executor, registry entry, OAuth provider/service, token refresh
profile, usage handler, and related test coverage and baselines.

src/shared/components/OAuthModal.js

@@ -226,7 +226,6 @@ export default function OAuthModal({ isOpen, provider, providerInfo, onSuccess,
       // Device code flow providers (must match oauth providers with flowType: "device_code")
       const deviceCodeProviders = [
         "github",
-        "qwen",
         "kiro",
         "kimi",
         "kimi-coding",

src/shared/components/Sidebar.js

@@ -21,7 +21,7 @@ const navItems = [
   { href: "/dashboard/endpoint", label: "Endpoint & Key", icon: "api" },
   { href: "/dashboard/providers", label: "Providers", icon: "dns" },
   // { href: "/dashboard/basic-chat", label: "Basic Chat", icon: "chat" }, // Hidden
-  { href: "/dashboard/combos", label: "Combos", icon: "layers" },
+  { href: "/dashboard/combos", label: "Combo & Vision Adapter", icon: "layers" },
   { href: "/dashboard/usage", label: "Usage", icon: "bar_chart" },
   { href: "/dashboard/quota", label: "Quota Tracker", icon: "data_usage" },
   { href: "/dashboard/token-saver", label: "Token Saver", icon: "savings" },