- Default mode changed to ondemand (pre-load first model, unload/load on switch)
- loadswap: load first model in VRAM, others in CPU RAM, swap on switch
- loadall: try to load all models in VRAM, offload to CPU RAM if OOM
- --nopreload: skip pre-loading in any mode, load on first request
- request_model() now properly handles all three modes
- Added _move_model_to_cpu() and _move_model_to_vram() for loadswap
- Fixed NameError: model_manager reference in request_model() (was using global singleton instead of self)
- Updated CLI help text for --loadall, --loadswap, --nopreload