add set_offload_strategy, Peak column in offload record, and offloading docs
- ComponentsManager.set_offload_strategy() to swap the offload strategy on
all managed models while auto offloading is enabled, with a fast test
- offload record repr gains a Peak column (peak allocated memory at each
decision) next to Available
- docs: explain the record and the Reason column, custom strategy examples
(sequential OffloadEverything + keeping co-scheduled models resident),
finding the bottleneck with the peak column, and tuning memory_reserve
from an OOM-retry record
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>