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/mitm/winElevated.js

@@ -7,13 +7,15 @@ const IS_WIN = process.platform === "win32";
  * Uses `net session` which only succeeds when elevated.
  */
 function isAdmin() {
-  if (!IS_WIN) return false;
-  try {
-    execSync("net session >nul 2>&1", { windowsHide: true, stdio: "ignore" });
-    return true;
-  } catch {
-    return false;
+  if (IS_WIN) {
+    try {
+      execSync("net session >nul 2>&1", { windowsHide: true, stdio: "ignore" });
+      return true;
+    } catch {
+      return false;
+    }
   }
+  return typeof process.getuid === "function" && process.getuid() === 0;
 }
 
 /**