Allow pull requests targeting master to declare same- and
cross-repository dependencies. Parse declarations with a tested Python
helper, apply exact dependency commits before the existing build matrix,
and rerun heavy CI only when an edited description changes the dependency
state.
Keep fork builds read-only and use a trusted workflow_run to validate
artifacts and post per-build dependency results. Document the supported
declaration forms and operational limits.
Assisted-by: Kiro:gpt-5.6-sol
Signed-off-by: zhangning21 <zhangning21@xiaomi.com>
