[Feature Request] Custom Headers and Payload Mapping For Custom Notifications

What problem will this feature address?

Description: I would like to request an enhancement to the Webhook Notification system to allow connecting to custom internal services more easily.

Current Behavior: Currently, the Webhook notification sends a fixed JSON payload to a specified URL. There is no option to define custom headers or inject specific key-value pairs (such as a channel_id or custom_token) that my proprietary service requires.

Desired Behavior: I propose adding a "Custom Data" or "Headers" section to the Webhook configuration form.

Option A (Headers): Allow users to add custom HTTP headers (e.g., X-Channel-ID: 12345 or Authorization: Bearer ).

Option B (Custom Payload/Key-Value): Allow users to define key-value pairs that get merged into the JSON payload.

Example: If I add channel: "my-ops-team", the final JSON sent by Dokploy would include "channel": "my-ops-team" alongside the standard deployment data.

Use Case: I am running a custom notification service that routes messages to specific internal channels based on a key-value pair in the payload. Without this, I have to build a middleware just to transform Dokploy's webhooks into a format my service accepts.

Describe the solution you'd like

X

Describe alternatives you've considered

Y

Additional context

No response

Will you send a PR to implement it?

Yes

The issue names no files, tests, or entry points. Start by locating the Webhook Notification configuration and delivery paths, then determine the scope and expected behavior for custom headers versus payload key-value mapping; done should include an agreed design and coverage for the selected behavior.