revert: restore production to the state before 730d0bd (PM/RBAC work moved to 'pm')

Their three commits (730d0bd, 5a9b543, 387edfb) reached production by push and
auto-deployed. 387edfb expects a users.username column that the live database does
not have, so POST /api/v1/auth/login was returning HTTP 500. Their schema changes
never applied either (projects still has only id, name, description, start_date,
pm_user_id, created_at), so nothing depends on the reverted code.

This commit sets the tree back to exactly a02b3ea — verified with git diff against
it — while keeping history linear: the work itself is preserved on 'pm' at 387edfb.

frontend/src/pages/Inventory/useInventoryData.ts

@@ -26,8 +26,8 @@ export interface InventoryData {
 
 export function useInventoryData(): InventoryData {
   const user = useAuthStore((s) => s.user);
-  const isSupervisor = user?.role === "supervisor";
-  const projectId = isSupervisor || user?.role === "pm" ? user?.project_id || undefined : undefined;
+  const isPM = user?.role === "pm";
+  const projectId = isPM ? user.project_id || undefined : undefined;
 
   const [warehouses, setWarehouses] = useState<Warehouse[]>([]);
   const [inventory, setInventory] = useState<InventoryRow[]>([]);