Refactor global styles and enhance MITM functionality

- Updated global CSS to implement a new brand color palette and improve light/dark theme consistency.
- Enhanced the MitmServerCard component to provide clearer user feedback regarding admin privileges.
- Filtered LLM combos in the CombosPage to ensure only relevant data is displayed.
- Improved APIPageClient layout for better usability and visual consistency.
- Added functionality to save and load DNS tool states in the MITM manager.
- Updated OAuth configuration URLs for Qwen to reflect the new endpoint structure.
- Refined tunnel management logic to improve reliability and user experience.

src/app/(dashboard)/dashboard/providers/[id]/page.js

@@ -762,15 +762,15 @@ export default function ProviderDetailPage() {
           <div className="min-w-0">
             <div className="flex items-center gap-3 flex-wrap">
               <h1 className="truncate text-2xl font-semibold tracking-tight sm:text-3xl">{providerInfo.name}</h1>
-              {providerInfo.notice?.apiKeyUrl && !providerInfo.deprecated && (
+              {(providerInfo.notice?.apiKeyUrl || providerInfo.notice?.signupUrl || providerInfo.website) && (
                 <a
-                  href={providerInfo.notice.apiKeyUrl}
+                  href={providerInfo.notice?.apiKeyUrl || providerInfo.notice?.signupUrl || providerInfo.website}
                   target="_blank"
                   rel="noopener noreferrer"
                   className="text-xs text-primary hover:underline inline-flex items-center gap-1"
                 >
                   <span className="material-symbols-outlined text-sm">open_in_new</span>
-                  Get API Key
+                  {providerInfo.notice?.apiKeyUrl ? "Get API Key" : "Sign up / Learn more"}
                 </a>
               )}
             </div>
@@ -911,20 +911,21 @@ export default function ProviderDetailPage() {
           </div>
 
           {connections.length === 0 ? (
-            <div className="text-center py-12">
-              <div className="inline-flex items-center justify-center w-16 h-16 rounded-full bg-primary/10 text-primary mb-4">
-                <span className="material-symbols-outlined text-[32px]">{isOAuth ? "lock" : "key"}</span>
+            <div className="flex flex-col gap-3 sm:flex-row sm:items-center sm:justify-between">
+              <div className="flex items-center gap-3">
+                <div className="inline-flex items-center justify-center w-9 h-9 rounded-full bg-primary/10 text-primary shrink-0">
+                  <span className="material-symbols-outlined text-[18px]">{isOAuth ? "lock" : "key"}</span>
+                </div>
+                <p className="text-sm text-text-muted">No connections yet</p>
               </div>
-              <p className="text-text-main font-medium mb-1">No connections yet</p>
-              <p className="text-sm text-text-muted mb-4">Add your first connection to get started</p>
               {!isCompatible && (
-                <div className="flex flex-col gap-2 justify-center sm:flex-row">
+                <div className="flex gap-2">
                   {providerId === "iflow" && (
-                    <Button icon="cookie" variant="secondary" onClick={() => setShowIFlowCookieModal(true)}>
-                      Cookie Auth
+                    <Button size="sm" icon="cookie" variant="secondary" onClick={() => setShowIFlowCookieModal(true)}>
+                      Cookie
                     </Button>
                   )}
-                  <Button icon="add" onClick={() => isOAuth ? setShowOAuthModal(true) : setShowAddApiKeyModal(true)}>
+                  <Button size="sm" icon="add" onClick={() => isOAuth ? setShowOAuthModal(true) : setShowAddApiKeyModal(true)}>
                     {providerId === "iflow" ? "OAuth" : "Add Connection"}
                   </Button>
                 </div>