Support per-approval-node notification templates in workflows

Summary

When a workflow job template contains multiple approval nodes, all approval nodes currently share the same set of notification templates (configured at the workflow job template and/or organisation level). There is no way to route different approval nodes to different notification channels.

Use case

Enterprise workflows commonly have multiple approval gates serving different purposes: security review, change management, finance sign-off. Each gate needs to notify a different audience through a different channel (for example, security team via Slack, change board via MS Teams webhook, finance via email).

Today all approval nodes fire the same notification templates, creating noise and slowing down response times. Operators work around this by nesting workflows (each with its own notification set) or by including the node name in Jinja2 templates, but neither approach provides true per-node routing.

Proposal

Add a notification_templates_approvals M2M field to WorkflowApprovalTemplate, exposed via the REST API at /api/v2/workflow_approval_templates/{id}/notification_templates_approvals/. When node-level templates are configured they take precedence; when empty, the existing WFJT/Organisation-level templates are used (fully backward compatible).

Related

• Upstream issues around approval notification friction: #8225, #14058, #5401, #13983