Rebrand 'Sign in with Casdoor' → 'Sign in with UmmahID'

src/app/auth/page.tsx

@@ -98,7 +98,7 @@ function AuthPageInner() {
 
           {/* Sign-in Methods */}
           <div className="space-y-3">
-            {/* Casdoor OIDC */}
+            {/* UmmahID OIDC */}
             <a
               href={getCasdoorUrl()}
               className="w-full flex items-center gap-4 px-5 py-4 rounded-2xl bg-green-900/20 border border-green-600/30 active:bg-green-900/30 transition-all touch-manipulation"
@@ -108,7 +108,7 @@ function AuthPageInner() {
               </div>
               <div className="text-left">
                 <span className="text-sm font-medium text-green-400 block">
-                  Sign in with Casdoor
+                  Sign in with UmmahID
                 </span>
                 <span className="text-xs text-gray-600">FalahOS Identity Service</span>
               </div>