reload-after-unload failed because RayDistributedExecutor.shutdown() killed
the actors but never removed the placement group — the GPUs stayed reserved
forever. remove it on shutdown.
studio generator management simplified to a single slot: one VideoGenerator
instance at a time, one load in flight at a time (409 otherwise), loading a
new config always releases the old instance, unload shuts it down and
deletes it. jobs wait out an in-flight preload and reuse it on config match.
GET /api/engine/logs: incremental tail of the server's stdout/stderr (ray
relays worker output to the driver, so this captures every rank).
SolitaryThinker
3a7e7fc69f