Preserve repository-root path whitespace

[hzw0813]

Summary

• stop applying JavaScript String.trim() to git rev-parse --show-toplevel output
• remove only Git's final line terminator, preserving valid trailing repository-root whitespace on POSIX filesystems
• add a regression with sibling directories repository and repository so the old implementation demonstrably resolves to the wrong path
• regenerate tracked dist and document the fix

Why

findRepository() currently runs Git from the correct candidate repository and then calls result.stdout.trim() before resolving the reported top-level path. A repository directory may legally end in whitespace on POSIX. If repository and sibling repository both exist, trimming the Git output silently changes path identity and can make ProofDiff return the sibling directory instead of the repository Git actually identified.

The fix strips only the output record's final newline (CRLF on Windows, LF elsewhere) and leaves all path characters untouched.

Verification

• full npm test passed after the change
• clean npm run clean && npm run build passed
• git diff --check passed
• generated dist/git.* refreshed
• temporary updater workflow/script removed from the final diff