ci: Build node-pc runtime on n8nio/base image

[ivov]

Summary

This PR rebuilds the runtime stage of the node-pc image (pointer-compressed Node.js) on top of n8nio/base:26.5.1 so we reuse the base's package layer, paths, and policies. What remains is only the Node swap.

Also drops the DHI registry login from the workflow, since nothing pulls dhi.io anymore.

Follow-up to: #35756 (comment)

Related Linear tickets, Github issues, and Community forum posts

https://app.notion.com/p/n8n/Halving-memory-usage-via-pointer-compression-3ac5b6e0c94f8005af87e93a9f837b53

Review / Merge checklist

• PR title and summary are descriptive. (conventions)
• Docs updated or follow-up ticket created.
• Tests included.
• PR Labeled with Backport to Beta, Backport to Stable, or Backport to v1 (if the PR is an urgent fix that needs to be backported)

[n8n-assistant]

PR review overview

Based on ownership of the 2 changed files in this PR:

Ownership	Files owned	Share	Source code	Test files	Misc
@n8n-io/qa-dx	2	100%	+5 / -40	+0 / -0	+0 / -0
Total	2	100%	+5 / -40	+0 / -0	+0 / -0

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[cubic-dev-ai]

No issues found across 2 files

Architecture diagram

sequenceDiagram
    participant WF as Workflow (CI)
    participant GHCR as GHCR Registry
    participant DHI as DHI Registry
    participant Build as Builder Stage (Alpine)
    participant Base as n8nio/base:26.5.1
    participant Runtime as Runtime Stage (node-pc)
    participant Cloud as Cloud Launch / AppArmor

    Note over WF,Cloud: CI Build Pipeline for node-pc Image

    WF->>GHCR: Login to Docker registries (push)
    WF->>Build: Build stage (compiles pointer-compressed Node)
    Build->>Build: Compile Node with v8_enable_pointer_compression

    Note over Base,Runtime: Runtime Stage (Dockerfile)
    Base->>Runtime: FROM n8nio/base:26.5.1 (multi-arch digest)
    Runtime->>Runtime: Remove stock Node binaries (node, npm, npx, corepack)
    Runtime->>Runtime: Remove /usr/local/bin/node
    Build->>Runtime: COPY compiled Node from builder stage
    Runtime->>Runtime: Verify Node version & pointer compression
    Runtime->>Runtime: Symlink /usr/local/bin/node to /usr/bin/node

    Note over Runtime,Cloud: Runtime Image Usage
    Cloud->>Runtime: Launch container (expects /usr/local/bin path)
    Runtime->>Cloud: Node runtime with pointer compression enabled

    Note over WF,DHI: DHI Registry Login Removed (no longer needed)

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[n8n-assistant]

Got released with n8n@2.36.0