* fix(channels): validate headless channel setup
* docs(channels): document headless provisioning
* fix(channels): repair setup metadata typing
* chore(channels): regenerate official channel catalog for env metadata
* fix(slack): keep mode-conditional env contract plugin-owned
Static --use-env declaration keeps only the unconditional SLACK_BOT_TOKEN;
socket-vs-HTTP conditional requirements (app token, signing secret) stay in
Slack's own setup validation so HTTP mode no longer demands an irrelevant
SLACK_APP_TOKEN.
* chore(sdk): regenerate api baselines and catalog after rebase
* fix(slack): align manifest env declaration with runtime contract
* chore(sdk): regenerate api baselines after rebase
* chore(sdk): regenerate api baselines after rebase
* chore(sdk): regenerate api baselines after rebase
