fix: preserve CODEOWNERS scope and require Node.js 22+

[ho991217]

Preserve the matching scope of patterns such as *.ts and docs/ when merging CODEOWNERS files, while retaining the meaning of root-level and explicitly anchored patterns.

Treat only ENOENT as a missing output file. Report other read errors with the file path and stop sync before overwriting any outputs.

Require Node.js 22.8 or later and replace picocolors with the built-in styleText from node:util for CLI output.

Add regression coverage and separate unit tests from CLI integration tests so only integration tests require a build.

Fixes #18
Fixes #20
Fixes #31

[Copilot]

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[Copilot]

Copilot review overview

🟡 Changes recommended

Critical test configuration and additional CLI, Windows path, and build-reference issues remain unresolved.

Review effort: Lite
Findings: 1 · 1

Open (2)

• Extend root Vitest configuration for unit test globals · New
• Normalize relative paths to POSIX separators for CODEOWNERS · New

[Copilot]

Copilot review overview

🔵 Needs a closer look

Address the three moderate issues involving stream validation and Vitest global configuration.

Review effort: Lite
Findings: None

Resolved since last review (2)

• Extend root Vitest configuration for unit test globals
• Normalize relative paths to POSIX separators for CODEOWNERS