Apply a unified diff patch across one or more files atomically.
All hunks across all files are validated in memory first (pure-Elixir backend) before any file is written to disk — partial mutations on error are impossible.
Backend selection:
- Inside a git work-tree: delegates to
git apply --whitespace=nowarn, which is itself atomic on failure. - Otherwise: pure-Elixir two-pass parser/applier.
v1 limitations: no binary diffs, no /dev/null create/delete hunks, no fuzzy
context matching.