Per the bake-in invariant: when no active beta exists, dev tracks
stable. Previously notify-chart-prod only bumped chart's main, so
a stable cut updated BMCD prod but left dev one cut behind until
the next beta or manual dispatch.
Now the job loops through {main, develop} and pushes the same
appVersion bump to both. Each branch push triggers its own BMCD
pipeline (pipeline-prod for main, pipeline-dev for develop), so
prod + dev both rebuild against the new ZDDC stable in parallel.
notify-chart-dev.yml continues to handle the beta-cut path
(advances develop ahead of main between stable cuts).