Root cause: base image paged_attn.py imports Triton context_attention_fwd
which does not exist on BI-V100 (no Triton). Our paged_attn.py replaces
it with PyTorch fallback but was NEVER deployed — missing from patch_ops.sh.
SYSTEM_DESIGN.md step 9 lists it, patch_ops.sh didn't have it.
Also deploys prefix_prefill.py as safety net.
Error was: paged_attn.py:203 NameError: name 'context_attention_fwd' is not defined
→ AsyncEngineDeadError → all requests 503