feat: write exit code to stderr on process termination

[Copilot]

Process was terminating silently without indicating exit code, making post-mortem debugging difficult in CI/CD environments.

Changes

• Exit code logging: Added console.error() before all process.exit() calls to write exit code to stderr

  • SIGINT handler (exit 130)
  • SIGTERM handler (exit 143)
  • Normal workflow completion (exit code from command)
  • Error handler (exit 1)

• Tests: Added integration tests verifying exit code appears in stderr for both successful and failed commands

Example

After changes, stderr output includes:

Process exiting with code: 42

This applies to all exit paths including signal termination, enabling log-based debugging of process lifecycle.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Write the process exit code to the stderr</issue_title>
<issue_description>If the process is killed, it dies silently. Write error code to stderr.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Write the process exit code to the stderr #94

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[github-actions]

Test Coverage Report

Metric	Coverage	Covered/Total
Lines	66.95%	695/1038
Statements	67.1%	716/1067
Functions	70.24%	85/121
Branches	62.46%	228/365

Coverage Thresholds

The project has the following coverage thresholds configured:

• Lines: 38%
• Statements: 38%
• Functions: 35%
• Branches: 30%

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Coverage report generated by `npm run test:coverage`