feat(whatsapp): add webhook registration and status endpoints (#13551)

## Description

Adds webhook configuration management for WhatsApp Cloud API channels,
allowing administrators to check webhook status and register webhooks
directly from Chatwoot without accessing Meta Business Manager.

## Type of change

- [ ] New feature (non-breaking change which adds functionality)


## Screenshots

<img width="1130" height="676" alt="Screenshot 2026-03-05 at 7 04 18 PM"
src="https://github.com/user-attachments/assets/f5dcd9dd-8827-42c5-a52b-1024012703c2"
/>
<img width="1101" height="651" alt="Screenshot 2026-03-05 at 7 04 29 PM"
src="https://github.com/user-attachments/assets/e0bd59f9-2a90-4f24-87c0-b79f21e721ee"
/>



## Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

app/javascript/dashboard/i18n/locale/en/inboxMgmt.json

@@ -685,6 +685,16 @@
           "SANDBOX": "Sandbox",
           "LIVE": "Live"
         }
+      },
+      "WEBHOOK": {
+        "TITLE": "Webhook Configuration",
+        "DESCRIPTION": "Webhook URL is required for your WhatsApp Business Account to receive messages from customers",
+        "ACTION_REQUIRED": "Webhook not configured",
+        "REGISTER_BUTTON": "Register Webhook",
+        "REGISTER_SUCCESS": "Webhook registered successfully",
+        "REGISTER_ERROR": "Failed to register webhook. Please try again.",
+        "CONFIGURED_SUCCESS": "Webhook configured successfully",
+        "URL_MISMATCH": "Webhook URL mismatch"
       }
     },
     "SETTINGS": "Settings",