fix: metadata type assertion for TS strict mode

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/colony/src/components/MessageItem.tsx

@@ -37,7 +37,7 @@ export function MessageItem({ message, replyTarget, onReply }: Props) {
   const isAgent = message.user.role === "agent";
   const isDeleted = !!message.deleted_at;
   const cfg = TYPE_CONFIG[message.type] || TYPE_CONFIG.text;
-  const meta = message.metadata as Record<string, unknown> | null;
+  const meta = message.metadata as Record<string, string> | null;
 
   return (
     <div
@@ -127,12 +127,12 @@ export function MessageItem({ message, replyTarget, onReply }: Props) {
           {/* Agent metadata strip */}
           {meta && isAgent && (
             <div className="mt-1 flex gap-3 text-[10px] text-muted-foreground opacity-50">
-              {meta.model && <span>{String(meta.model)}</span>}
-              {meta.hostname && <span>{String(meta.hostname)}</span>}
-              {meta.cwd && <span>{String(meta.cwd)}</span>}
+              {meta.model && <span>{meta.model}</span>}
+              {meta.hostname && <span>{meta.hostname}</span>}
+              {meta.cwd && <span>{meta.cwd}</span>}
               {meta.skill && (
                 <span className="text-[var(--color-msg-plan)]">
-                  {String(meta.skill)}
+                  {meta.skill}
                 </span>
               )}
             </div>