feat(core): Implement lifecycle hooks to support streaming responses (no-changelog)

[schrothbn]

Summary

This PR adds infrastructure to support streaming responses:

• Add new response mode streaming
• Add response to execution data while streaming
• Add lifecycle hooks to send a chunk to the response
• Add message and hook for workers to support streaming in queue mode
• Close an open response at the end of execution

Related Linear tickets, Github issues, and Community forum posts

https://linear.app/n8n/issue/AI-1033/add-response-mode-streaming
https://linear.app/n8n/issue/AI-1032/add-lifecycle-hooks-for-sending-chunks

Review / Merge checklist

• PR title and summary are descriptive. (conventions)
• Docs updated or follow-up ticket created.
• Tests included.
• PR Labeled with release/backport (if the PR is an urgent fix that needs to be backported)

[codecov]

Codecov Report

Attention: Patch coverage is 27.02703% with 27 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
packages/cli/src/webhooks/webhook-helpers.ts	0.00%	10 Missing ⚠️
packages/cli/src/active-executions.ts	40.00%	6 Missing ⚠️
...n-engine/node-execution-context/execute-context.ts	0.00%	5 Missing ⚠️
packages/cli/src/scaling/job-processor.ts	33.33%	2 Missing ⚠️
packages/cli/src/scaling/scaling.service.ts	0.00%	2 Missing ⚠️
packages/cli/src/workflow-runner.ts	60.00%	2 Missing ⚠️

📢 Thoughts on this report? Let us know!