fix(ci): set Node version for server image validation

[l1shen]

The server_image job installed dependencies without selecting the project Node version. In CI run 33938701620, installation took 81 seconds, while the server and quality jobs that set up Node 26 took about 1–2 seconds. An unmatched Node ABI can make isolated-vm fall back to source compilation; the existing logs do not isolate its installation time.

Add the same actions/setup-node step used by the other jobs, reading .node-version before bun install. This makes the image validation runner use the project Node version and its supported native prebuilds.

Validation: bun run format and bun run check passed before the branch was created. Docker validation was not rerun locally because the Docker daemon is unavailable. The actual installation speedup remains to be verified in CI.

[coderabbitai]

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• .github/workflows/ci.yaml

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Summary by CodeRabbit

• Chores
  • Updated the server image verification workflow to use the project’s specified Node.js version before installing dependencies and running checks.

Walkthrough

The server_image CI job now runs actions/setup-node@v6. The step reads the Node version from .node-version before the job installs dependencies and verifies the server image.

Merge Risk: ⚪ Minimal · up to 04dde

The server image CI job now uses the repository’s Node version before installing dependencies, aligning it with the intended runtime configuration. No merge-blocking risk is identified.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title follows the required <type>(<scope>): <subject> format and accurately describes the Node version update for server image validation.
Description check	✅ Passed	The description explains the CI change, its purpose, validation status, and the remaining CI verification.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

✨ Simplify code

• Create PR with simplified code

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