Add US Only filter button for international students

src/pages/Index.tsx

@@ -106,7 +106,7 @@ const Index = () => {
   };
 
   // Define US states and territories that should be included in "US Only" filter
-  const usRegions = new Set(["USA", "PENNSYLVANIA", "New Mexico", "Michigan", "Tennessee", "Hawaii"]);
+  const usRegions = new Set(["USA"]);
 
   // Toggle a single tag
   const toggleTag = (tag: string) => {
@@ -251,7 +251,7 @@ const Index = () => {
                   }
                 }}
               >
-                🇺🇸 US Only
+                US Only
               </Button>
               
               {/* Display selected countries */}