feat(cli): add `--all` option to sync unpicked first-parent ancestors (…

…#17)

feat: detect already-synced commits; add `--allow-empty` flag, tests …

…and docs (#16)

* test: cover allow-empty behavior

* fix: satisfy clippy collapsible if

* fix: skip lfs resolution for symlink checks

* test: cover operations_already_applied

* test: expand operations_already_applied coverage

* test: cover main and lfs pointer paths

* fix: satisfy clippy in tests

* test: cover operations mismatch paths

* fix: make missing source test hit error

* test: add coverage for dirty repo and lfs

* test: cover mapping and path validation

* test: cover lfs resolution in applied check

* test: cover mapping and normalization branches

* test: cover symlink applied check

chore: add license file

fix: fix the issue where a patch which contains binaries can not be a…

…pplied

test: expand coverage for sync helpers

ci: add mac targets to release

fix: vendor libgit2 and openssl

fix: commit lfs pointers before smudging

docs: add commit message format guidelines

Refine signature overrides helper