Refactor command building (deduplicate HF/local paths) and add
flags for better performance:
- --parallel 1: studio is single-user, so only 1 inference slot
is needed. The previous auto-detect picked 4 slots, wasting
VRAM on 3 unused KV caches.
- --flash-attn on: force flash attention for faster inference.
Default is "auto" which may not always enable it.
- --fit on: auto-adjust parameters to fit in available device
memory. Already the default but now explicit.
Also cleaned up the duplicated command building for HF vs local
mode into a single block.
80d84a5b5f