fix: use eager attention for MiniCPM4.1-8B to prevent SDPA crash, fix Nemotron Parse processor format

fix: switch Core Router to AutoModelForCausalLM for generate support, fix Nemotron Parse inference with AutoProcessor

fix: block flash_attn at runtime with sys.modules=None to prevent FA2 on HF ZeroGPU where flash_attn is pre-installed

fix: resolve infinite recursion in flash_attn patch by capturing original get_imports before patching

fix: replace flash_attn mock with get_imports patch to properly disable FA2 for MiniCPM4.1-8B and Nemotron Parse

fix: correct vision model dtype, Nemotron Parse model ID, and patch missing is_torch_fx_available

feat: add Parallel Vision Engine — MiniCPM-V and Nemotron Parse fire async with confidence-score arbiter