test: DSv4-Pro B300 vLLM - bump to v0.20.2, fine conc sweep, no cpu offload

- Image v0.20.0-cu130 -> v0.20.2 (cu129; no -cu130 build exists for
  v0.20.2 on Docker Hub). Same image B200 Kimi runs cleanly on.
- Strip all offloading=cpu entries (G+H runs showed both crash and
  hang on the cpu path; v0.20.2 may or may not fix the underlying
  DSv4 issue, isolate to none first).
- Replace conc-lists with fine sweep [64, 70, 76, 82] across all 4
  parallelism configs to find the cliff at 6-conc resolution.
  16 jobs total.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: cquil11

.github/configs/nvidia-master.yaml

@@ -2811,7 +2811,7 @@ dsv4-fp8-h200-sglang-mtp:
   # field, so dp-attn=true is used as the existing vLLM script switch for DP4
   # layouts on 4 allocated GPUs.
 dsv4-fp4-b300-vllm:
-  image: vllm/vllm-openai:v0.20.0-cu130
+  image: vllm/vllm-openai:v0.20.2
   model: deepseek-ai/DeepSeek-V4-Pro
   model-prefix: dsv4
   runner: b300
@@ -2844,14 +2844,10 @@ dsv4-fp4-b300-vllm:
     agentic-coding:
     - duration: 1800
       search-space:
-      - { tp: 4, offloading: none, conc-list: [16, 32, 64] }
-      - { tp: 8, offloading: none, conc-list: [16, 32, 64] }
-      - { tp: 4, ep: 4, dp-attn: true, offloading: none, conc-list: [64, 128, 256] }
-      - { tp: 8, ep: 8, dp-attn: true, offloading: none, conc-list: [128, 256, 512] }
-      - { tp: 4, offloading: cpu,  conc-list: [16, 32, 64] }
-      - { tp: 8, offloading: cpu,  conc-list: [16, 32, 64] }
-      - { tp: 4, ep: 4, dp-attn: true, offloading: cpu,  conc-list: [64, 128, 256] }
-      - { tp: 8, ep: 8, dp-attn: true, offloading: cpu,  conc-list: [128, 256, 512] }
+      - { tp: 4, offloading: none, conc-list: [64, 70, 76, 82] }
+      - { tp: 8, offloading: none, conc-list: [64, 70, 76, 82] }
+      - { tp: 4, ep: 4, dp-attn: true, offloading: none, conc-list: [64, 70, 76, 82] }
+      - { tp: 8, ep: 8, dp-attn: true, offloading: none, conc-list: [64, 70, 76, 82] }
 
 dsv4-fp4-b300-trt:
   image: ghcr.io#semianalysisai/trtllm-deepseek-v4:feat-deepseek_v4-9aa3715