Phase 1 run-control semantics and run_state events

src/gateway/ui/pages/chat.js

@@ -715,6 +715,10 @@ async function sendMessage(client, overrideText) {
   scrollToBottom();
 
   // Create placeholder for assistant response
+  const statusLine = document.createElement('div');
+  statusLine.className = 'px-1 text-[11px] leading-none text-zinc-500 select-none hidden';
+  statusLine.textContent = 'Run status: queued';
+  _elements.messages.appendChild(statusLine);
   const placeholder = document.createElement('div');
   placeholder.className = 'rounded-lg px-3.5 py-2.5 text-sm leading-relaxed break-words whitespace-pre-wrap bg-zinc-900 border border-zinc-800 text-zinc-50 streaming-cursor';
   placeholder.innerHTML = '<span class="text-zinc-500">Thinking...</span>';
@@ -759,6 +763,22 @@ async function sendMessage(client, overrideText) {
       scrollToBottom();
     });
 
+    stream.on('run_state', (data) => {
+      if (!data || !data.state) {
+        return;
+      }
+      const labels = {
+        start: 'Run status: working',
+        cancel_requested: 'Run status: cancellation requested',
+        cancelled: 'Run status: cancelled',
+        complete: 'Run status: complete',
+        error: `Run status: error${data.message ? ` (${data.message})` : ''}`,
+      };
+      statusLine.textContent = labels[data.state] || `Run status: ${data.state}`;
+      statusLine.classList.remove('hidden');
+      scrollToBottom();
+    });
+
     const done = await stream.result;
     const content = done?.content ?? done?.text ?? '(no response)';
     const assistantMessage = createMessageEl('assistant', content, Date.now());
@@ -771,6 +791,7 @@ async function sendMessage(client, overrideText) {
     _cancelling = false;
     updateSendButton();
     clearPendingAttachments();
+    statusLine.remove();
     scrollToBottom();
   }
 }