* models: dual-slot backend (qcom/usbgpu) with ref-based downloads
* models: restore get_active_source and the usbgpu-to-qcom fallback
* models: fix per-slot validation and cap mismatched-source refetches
* ui/models: select models by ref and seed the usbgpu slot on migration
* models: drop defensive attribute guards on capnp bundles
* models: remove vestigial fetcher state and dead fallbacks
* models: resolve the active bundle from the active source slot only
* models: pass the usbgpu kwarg through the modeld test stubs
* models: resolve the displayed model from the active slot in ui_state
* models: correct the validation memo type hint
* models: drop docstrings that restate the function name
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Co-authored-by: Jason Wen <haibin.wen3@gmail.com>
Nayan
da28afca91