Wires the whisper backend through the new tuning helper. gpu_offloaded
combines a compile-time feature check (whisper-vulkan, in default
features) with a runtime libvulkan probe via the hardware module. If
libvulkan1 is missing on Linux, whisper-rs's vulkan backend silently
falls back to CPU, so we should not reduce threads in that case.
The old magnotia_core::constants::inference_thread_count import is
replaced by tuning::{inference_thread_count, Workload}. The constants
module's helper is removed in Task 6.1 once the LLM call site has
also migrated.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
e715da3b54