test: cover active-thread participant narrowing

test: cover concurrent group collaboration threads

test: expand workflow collaboration coverage

test: cover coordinator scope with alternate default account

test: extend coordinator scope matrix for active threads

refactor: generalize coordinator collective scope

refactor: model group collaboration scope explicitly

fix: expand coordinator collective direct replies

refactor: remove environment-specific coordinator assumptions

fix: resolve coordinator account from feishu defaults

fix: keep explicit main inside peer collaboration

fix: resume thread-scoped collaboration tasks

fix: retry transient feishu send transport failures

fix: trigger hidden-main owner kickoff after peer assessments

fix: stabilize feishu alias recognition and display mentions