fix: prevent typing indicator leak on agent run exceptions and follow-up race

Two leak paths caused Discord typing indicators to persist indefinitely:

1. If runAgent() threw before turnController.finish(), setTyping(false)
   was never called. Wrap the agent run in try/finally to guarantee cleanup.

2. Follow-up message piping called setTyping(true) fire-and-forget. If
   the Promise resolved after finish()'s setTyping(false), the typing
   interval was recreated with nobody to clear it. Await the call to
   serialize the on/off sequence.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/message-runtime.ts

@@ -345,6 +345,7 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
 
       await turnController.start();
 
+      try {
         const output = await runAgent(group, prompt, chatJid, runId, (result) =>
           turnController.handleOutput(result),
         );
@@ -372,6 +373,12 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
         );
 
         return true;
+      } finally {
+        // Safety net: always clear typing even if runAgent() or finish() throws.
+        // Prevents stuck typing indicators when exceptions bypass the normal
+        // turnController.finish() → setTyping(false) path.
+        await channel.setTyping?.(chatJid, false);
+      }
     }
   };
 
@@ -523,7 +530,7 @@ export function createMessageRuntime(deps: MessageRuntimeDeps): {
                   endSeq,
                 );
               }
-              channel
+              await channel
                 .setTyping?.(chatJid, true)
                 ?.catch((err) =>
                   logger.warn(