Fix Git structured output parsing

[maniramezan]

Summary

• parse diff paths using NUL-delimited output
• preserve unusual filenames, rename pairs, and submodule paths containing spaces
• fail typed workflows on malformed output instead of returning clean or empty results
• preserve branch listing options and force capture for structured workflows

Validation

• full all-traits suite (410 tests)
• coverage 90.77%
• strict formatting, trait and DocC validators
• DocC generation and git diff --check