Agent rules for this repo

Dev: cmake -S . -B build -DCMAKE_BUILD_TYPE=Release && cmake --build build -j && ctest --test-dir build -V.
Style: exact, minimal diffs. Prefer editing existing files over creating new ones.
NEVER use em dashes (U+2014) anywhere: not in code, docs, comments, commit messages, or chat output. Use a hyphen, comma, or colon instead.
Verify through execution: run the suite after behavior changes.
Destructive endpoints stay dry-run by default, date-guarded where remote data is at stake, and scoped to the claimed directory or allowed roots.

See also: README.md, INSTALL.md, CLI.md, PLAN.md, REGISTRY.md, AGENTS.md, skills/versiond-admin/SKILL.md.