fix: typing indicator now shows on every message, not just the first

Two issues fixed:
- Use 'paused' instead of 'available' to stop typing. Baileys'
  sendPresenceUpdate('available') sends a global <presence> stanza and
  ignores the JID, so chatstate never left 'composing' and WhatsApp
  suppressed duplicate composing notifications per XEP-0085.
- Add setTyping call when piping messages to an already-running
  container. Previously only the first message (which spawns a new
  container) triggered the typing indicator.

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

src/channels/whatsapp.ts

@@ -218,7 +218,9 @@ export class WhatsAppChannel implements Channel {
 
   async setTyping(jid: string, isTyping: boolean): Promise<void> {
     try {
-      await this.sock.sendPresenceUpdate(isTyping ? 'composing' : 'available', jid);
+      const status = isTyping ? 'composing' : 'paused';
+      logger.debug({ jid, status }, 'Sending presence update');
+      await this.sock.sendPresenceUpdate(status, jid);
     } catch (err) {
       logger.debug({ jid, err }, 'Failed to update typing status');
     }