#523 - Quick wins: runtime stability, CI alignment, and config/test hygiene

[brijesh-amin]

Parent: #523

Objective

Deliver low-effort, high-impact updates that reduce immediate operational risk and improve signal quality.

In scope

• Remove error rethrow after HTTP response in src/index.ts
• Ensure fatal server bootstrap failures exit non-zero in src/server.ts
• Align GitHub Actions runtime with supported Node version and update action versions
• Update Vitest include patterns to cover JS + TS specs
• Refresh docs/tooling references that are clearly outdated

Acceptance criteria

• API error middleware does not rethrow after sending response
• Startup failure produces non-zero process exit
• CI runs on supported Node version and passes
• Test runner discovers both *.spec.js and *.spec.ts
• Updated docs reflect current commands and runtime expectations

Notes

Keep this issue focused on minimal-risk, behavior-preserving changes.