feat: support user-related placeholders in submission templates and standardize display time to Asia/Bangkok timezone

app/admin/form/[id]/result/[submissionId]/client.tsx

@@ -77,14 +77,14 @@ export default function SubmissionDetailClient({
           <div className="flex items-center gap-2 text-muted-foreground">
             <Calendar className="w-4 h-4 shrink-0" />
             <span className="font-semibold text-foreground">Initial Submission:</span>
-            <span>{new Date(submission.submittedAt).toLocaleString(undefined, { hour12: false })}</span>
+            <span>{new Date(submission.submittedAt).toLocaleString("en-US", { timeZone: "Asia/Bangkok", hour12: false })}</span>
           </div>
           {editHistory.length > 0 && (
             <div className="flex flex-col mt-2 pt-2 border-t">
               <span className="font-semibold text-foreground mb-1">Edit History:</span>
               <ul className="list-disc list-inside text-xs text-muted-foreground space-y-1">
                 {editHistory.map((edit, idx) => (
-                  <li key={idx}>Edited at {new Date(edit.editedAt).toLocaleString(undefined, { hour12: false })}</li>
+                  <li key={idx}>Edited at {new Date(edit.editedAt).toLocaleString("en-US", { timeZone: "Asia/Bangkok", hour12: false })}</li>
                 ))}
               </ul>
             </div>
@@ -197,7 +197,7 @@ export default function SubmissionDetailClient({
                           >
                             <div className="flex items-center gap-1 text-xs text-muted-foreground">
                               <Clock className="w-3 h-3 shrink-0" />
-                              <span>{new Date(entry.editedAt).toLocaleString()}</span>
+                              <span>{new Date(entry.editedAt).toLocaleString("en-US", { timeZone: "Asia/Bangkok", hour12: false })}</span>
                             </div>
                             <span className="text-sm text-foreground/80 whitespace-pre-wrap leading-relaxed">
                               {entry.answer || <span className="italic text-muted-foreground">No response</span>}