Optionally include project name in Slack deployment notification titles

[dunctk]

Description

Slack deployment notifications use generic titles such as Deployment failed and New version successfully deployed. When several Coolify projects send notifications to the same Slack channel, it is difficult to identify the affected project from the notification title alone.

Add an optional setting under /notifications/slack that prefixes deployment notification titles with the project name.

Implemented here: #10928

Expected behavior

When enabled, Slack deployment titles should use the following format:

• My Project: Deployment failed
• My Project: New version successfully deployed

When disabled, the existing titles should remain unchanged.

Acceptance criteria

• A project-name title option is available under the deployment settings on /notifications/slack.
• The option applies to successful and failed deployment Slack notifications.
• The option defaults to disabled for backward compatibility.
• Notifications without project context remain unchanged.