The extracted findGitBash builds Windows-style candidate paths, but the
vitest suite (and any POSIX CI host) runs with posix path.join, which
mangles 'C:\Program Files' + segments into slash-joined paths and broke
the invalid-override fallback test. Use path.win32.join explicitly so
candidate construction is host-independent.
Port the HERMES_GIT_BASH_PATH env var check from main.cjs to main.ts
after the TS conversion. Also extract findGitBash to a dedicated module
for testability and add focused regression tests for override precedence
and invalid-override fallback.