feat(messaging): read receipts + ack convention

Closes the fire-and-forget gap the user hit: the sender now sees when a message
is read. When markMessageRead fires, the read event carries the reader, and the
watch stream renders it as a receipt:

  AgentHub: ✓ Read         MSG-0002  read by windows-claude

Plus an ack convention in the implementer guide: when you act on a message-
request, send a brief "on it …" + a result message — so the sender sees progress,
not silence. (Board-side activity feed with messages is folded into TSK-0032.)

Bump 0.8.0 -> 0.8.1.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "agenthub",
-  "version": "0.8.0",
+  "version": "0.8.1",
   "description": "Local coordination layer for AI coding agents",
   "type": "module",
   "main": "./dist/index.js",

src/cli/commands/watch.ts

@@ -80,6 +80,10 @@ function describeEvent(event: AgentHubEvent): { label: string; detail: string }
     case 'memory':
       return { label: 'Memory', detail: event.title ?? '' };
     case 'message':
+      // A read message surfaces to the SENDER as a delivery/read receipt.
+      if (event.action === 'updated' && event.status === 'read') {
+        return { label: '✓ Read', detail: event.assignedTo ? `read by ${event.assignedTo}` : 'read' };
+      }
       return { label: 'Message', detail: event.title ?? '' };
     default:
       // 'agent' presence events are formatted in formatEvent() before reaching

src/cli/index.ts

@@ -117,7 +117,7 @@ async function runRemote(serverUrl: string, fn: () => Promise<void>): Promise<vo
 export function createProgram(cwd: string): Command {
   const program = new Command('agenthub')
     .description('Local coordination layer for AI coding agents')
-    .version('0.8.0')
+    .version('0.8.1')
     .option('--server <url>', 'AgentHub server URL (env: AGENTHUB_SERVER)');
 
   program

src/core/templates.ts

@@ -59,6 +59,10 @@ claims it, and returns the task + its handoff. Then:
 then \`agenthub task review <id>\` + \`agenthub memory add …\`, then \`agenthub work\` again
 (run it in the background so the wait doesn't tie up your turn).
 
+**Messages:** \`agenthub_work\` surfaces messages addressed to you (or check \`agenthub_inbox\`).
+When you act on a message-request, send a short ack with \`agenthub_message\` ("on it ...") and
+a result message when done — so the sender sees progress + outcome, not silence.
+
 ⚠️ NEVER close a task yourself (no \`agenthub_task_done\` / \`agenthub task done\`) — only the
 architect approves and closes. You drive the tools yourself; the human doesn't type them for you.
 `;

src/server/routes.ts

@@ -300,7 +300,12 @@ export async function registerRoutes(app: FastifyInstance, cwd: string): Promise
     const { id } = request.params as { id: string };
     try {
       const message = markMessageRead(cwd, id);
-      emitChange({ type: 'message', action: 'updated', id: message.id, status: 'read' }, message.updatedAt);
+      // Read receipt: carry the reader (to) so the sender's stream shows
+      // "✓ MSG-xxxx read by <agent>".
+      emitChange(
+        { type: 'message', action: 'updated', id: message.id, status: 'read', title: `${message.from} → ${message.to}`, assignedTo: message.to },
+        message.updatedAt,
+      );
       return message;
     } catch (err) {
       return badRequest(reply, err instanceof Error ? err.message : 'Message not found');