fix(frontend): repair merge-damaged syntax left by the pm/RBAC revert cycle

Stray braces in App.tsx / ChangeInventoryPage.tsx, an orphaned admin gate in ArrivalsPage.tsx, and a literal revert commit subject pasted into LoginPage.tsx — all made the committed tree unbuildable.

frontend/src/pages/Inventory/ArrivalsPage.tsx

@@ -268,8 +268,6 @@ export function ArrivalsPage() {
     }
   };
 
-  if (!isAdmin && !isPM) {
-
   if (!canAccess) {
 
     return (

frontend/src/pages/Inventory/ChangeInventoryPage.tsx

@@ -573,7 +573,6 @@ export function ChangeInventoryPage() {
     if (type === "PROJECT_TRANSFER") {
       return !!(whId && toProjectId && matTxt.trim() && unitTxt.trim() && parseNum(qty) > 0);
     }
-    }
     if (type === "TRANSFER") return !!(fromId && toId && matTxt.trim() && rows.some((r) => parseNum(r.qty) > 0));
     if (type === "RETURN") return !!(whId && matTxt.trim() && rows.some((r) => parseNum(r.qty) > 0));
     if (type === "FOUND") {