ci(api): unit test sharding (3x) + path filters + composite action (#129)
- Split 2,114 unit tests across 3 parallel shards using vitest --shard
(~60% faster wall time)
- Add path filters for PRs: skip CI for docs-only or non-code changes.
Full suite always runs on push to main.
- Include composite setup action + lexicons cache + dependency graph
(combines Phase 2 + Phase 3 changes)
authored by