fix(agent-bot): Dispatch conversation_status_changed event to agent bots (#14002)

Agent bots assigned to a conversation were not receiving
`conversation_status_changed` webhook events. This meant bots could not
react to status transitions like moving a conversation to **pending**.
The deprecated `conversation_opened` and `conversation_resolved` events
were still being delivered, but the newer unified
`conversation_status_changed` event was silently dropped because
`AgentBotListener` had no handler for it.


## What changed

- Added `conversation_status_changed` handler to `AgentBotListener`,
matching the pattern already used by `WebhookListener`. The payload
includes `changed_attributes` so bots know which status transition
occurred.

## How to test

1. Configure an agent bot with an `outgoing_url` (e.g. a webhook.site
endpoint).
2. Assign the bot to an inbox or conversation.
3. Change a conversation's status to **pending** (or any other status).
4. Verify the bot receives a `conversation_status_changed` event with
the correct `changed_attributes`.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Muhsin <12408980+muhsin-k@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/listeners/agent_bot_listener.rb

@@ -15,6 +15,15 @@ class AgentBotListener < BaseListener
     agent_bots_for(inbox, conversation).each { |agent_bot| process_webhook_bot_event(agent_bot, payload) }
   end
 
+  def conversation_status_changed(event)
+    conversation = extract_conversation_and_account(event)[0]
+    changed_attributes = extract_changed_attributes(event)
+    inbox = conversation.inbox
+    event_name = __method__.to_s
+    payload = conversation.webhook_data.merge(event: event_name, changed_attributes: changed_attributes)
+    agent_bots_for(inbox, conversation).each { |agent_bot| process_webhook_bot_event(agent_bot, payload) }
+  end
+
   def conversation_updated(event)
     conversation = extract_conversation_and_account(event)[0]
     changed_attributes = extract_changed_attributes(event)