fix(cluster): use a separate HTTP server for debugPort

[dvd233]

Configuring debugPort for a plain HTTP application calls listen() twice on the same HTTP server, preventing both configured endpoints from becoming usable. Create a separate HTTP server for the debug listener, matching the existing HTTPS path.

Add real cluster regression coverage for HTTP with the default hostname, HTTP with an explicit hostname, and HTTPS with an HTTP debug port. Each case requests both endpoints and verifies that both ports are released after shutdown.

Validation on Node.js 22.23.2:

• Focused Vitest run: debug-port.test.ts, worker-protocol.test.ts, and https.test.ts — 20 tests passed. The new regression was also rerun after final test cleanup — 3 tests passed.
• Before the production fix, the two HTTP regression cases timed out; the HTTPS case passed.
• Cluster package tsc --noEmit, touched-file oxlint --type-aware --type-check, and oxfmt --check passed.

The focused tests used the package's Vitest entry point and original configuration directly because the local Windows utoo launcher failed before starting Vitest. A full monorepo/CI run was not performed.

Summary by CodeRabbit

• Bug Fixes
  • HTTP workers with a configured debug port now serve debug traffic through a separate HTTP server, keeping the application and debug endpoints available independently.

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ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: defaults
• Review profile: CHILL
• Plan: Advanced
• Run ID: 44e20f9e-42ba-402c-824c-d02affde29d0

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📥 Commits

Reviewing files that changed from the base of the PR and between e9cc326 and dce17f8.

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📒 Files selected for processing (5)

• packages/cluster/src/worker_protocol/app.ts
• packages/cluster/test/debug-port.test.ts
• packages/cluster/test/fixtures/apps/http-debug-server/app/router.js
• packages/cluster/test/fixtures/apps/http-debug-server/config/config.default.js
• packages/cluster/test/fixtures/apps/http-debug-server/package.json

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📝 Walkthrough

Walkthrough

HTTP workers with a configured debug port now use a separate HTTP server instead of the application server. New cluster tests cover HTTP and HTTPS endpoints, hostname settings, and port closure after app shutdown.

Changes

HTTP debug server

Layer / File(s)	Summary
Separate debug server and test fixture packages/cluster/src/worker_protocol/app.ts, packages/cluster/test/fixtures/apps/http-debug-server/*	HTTP workers with debugPort now use a separate HTTP server. The fixture configures the listener hostname and responds to GET /.
Endpoint and shutdown tests packages/cluster/test/debug-port.test.ts	Tests cover HTTP with unset and explicit hostnames, HTTPS, responses from both ports, and port closure after the app stops.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

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Merge Risk: ⚪ Minimal · up to dce17

HTTP applications with a configured debug port no longer call listen() twice on the same server. No concrete merge risk was found, and the new cluster tests cover the changed behavior.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 4 files. (1 skipped: 1…	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: using a separate HTTP server for the cluster debug port.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

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Full details: Docstring Coverage

Explanation

Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 3 functions across 4 files. (1 skipped: 1 unsupported.)

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✨ Finishing Touches

🧪 Generate unit tests (beta)

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