test: ensure the target dir exists

test: add missing target_dir variable

fix: add missing call to into

fix: fix invalid type

test: use a distinct target-dir per test

test: add a test on the sources generated for the runner

docs(README): mention that MacOS is also tested

chore(release): prepare multivers-runner 0.3.1

test: feature-gate a test that only supports Linux and Windows

ci: add macos-26-intel in the test matrix

fix(multivers-runner): properly set temp file permissions for unix

style: use context() instead of ok_or_else() with a single str

refactor: move options into various subsections

chore(release): prepare for cargo-multivers 0.11.0

chore(release): prepare multivers-runner 0.3.0