feat: allow agent bots to toggle typing status (#13705)

Agent bot conversations now feel more natural because AgentBot tokens
can toggle typing status, so end users see a live typing indicator in
the widget while the bot is preparing a reply. This keeps the
interaction responsive and human-like without weakening token
authorization boundaries.

## Closes
- https://github.com/chatwoot/chatwoot/issues/8928
- https://linear.app/chatwoot/issue/CW-5205

## How to test
1. Open the widget and start a conversation as a customer.
2. Connect an AgentBot to the same inbox.
3. Trigger `toggle_typing_status` with the AgentBot token
(`typing_status: on`).
4. Confirm the customer sees the typing indicator in the widget.
5. Trigger `toggle_typing_status` with `typing_status: off` and confirm
the indicator disappears.

## What changed
- Added `toggle_typing_status` to bot-accessible conversation endpoints.
- Restricted bot-accessible endpoint usage to `AgentBot` token owners
only (non-user tokens like `PlatformApp` remain unauthorized).
- Updated typing status flow to preserve AgentBot identity in
dispatch/broadcast paths.
- Added request coverage for AgentBot success and PlatformApp
unauthorized behavior.
- Added Swagger documentation for `POST
/api/v1/accounts/{account_id}/conversations/{conversation_id}/toggle_typing_status`
and regenerated swagger artifacts.

swagger/paths/application/conversation/toggle_typing_status.yml

@@ -0,0 +1,41 @@
+tags:
+  - Conversations
+operationId: toggle-typing-status-of-a-conversation
+summary: Toggle Typing Status
+description: Toggles the typing status for a conversation.
+security:
+  - userApiKey: []
+  - agentBotApiKey: []
+requestBody:
+  required: true
+  content:
+    application/json:
+      schema:
+        type: object
+        required:
+          - typing_status
+        properties:
+          typing_status:
+            type: string
+            enum: ['on', 'off']
+            description: Typing status to set.
+            example: 'on'
+          is_private:
+            type: boolean
+            description: Whether the typing event is for private notes.
+            example: false
+responses:
+  '200':
+    description: Success
+  '401':
+    description: Unauthorized
+    content:
+      application/json:
+        schema:
+          $ref: '#/components/schemas/bad_request_error'
+  '404':
+    description: Conversation not found
+    content:
+      application/json:
+        schema:
+          $ref: '#/components/schemas/bad_request_error'