feat(agent-zero): Zulip adapter with A2A protocol for kagentz

New project: agent-zero-zulip/ — direct Zulip integration for Agent Zero
agents using A2A protocol internally.

Architecture:
  kagentz (CT 105) ┌──────────────────────┐
                    │ Zulip Adapter  ◄──►  │ Agent Zero
                    │ polls Zulip    A2A   │ Docker container
                    │ port 8001            │
                    └──────────────────────┘

- adapter.py: Zulip event queue poller + A2A client
- No intermediate bridge — direct kagentz ↔ Zulip
- Heartbeat, reconnection, placeholder→edit streaming
- Designed for re-use: scottdenya, future Agent Zero agents

agent-zero-zulip/config.yaml.example

@@ -0,0 +1,13 @@
+# Agent Zero Zulip Adapter Configuration
+# Copy to config.yaml and fill in credentials
+
+zulip:
+  site: https://chat.sysloggh.net
+  email: kagentz-bot@chat.sysloggh.net
+  api_key: "<your-api-key>"
+  stream: agent-hub
+
+agent:
+  name: kagentz
+  a2a_url: http://localhost:8001/a2a
+  a2a_token: 8zNgdOEXzYxjQvTl