feat(erp-tune): run 7 launched on pfi-gx10 (opening-split slot + mask union) — config, launcher, builder, runbook; erp-seat: pin vLLM nightly 311b3513 (forced tool_choice 1/9 -> 6/9, round trip clean), README on the gemma4-parser design limit

stacks/erp-seat/compose.yaml

@@ -12,7 +12,7 @@ name: erp-seat
 
 services:
   vllm-erp-seat:
-    image: ${ERP_IMAGE:-vllm/vllm-openai:v0.26.0}
+    image: ${ERP_IMAGE:-vllm/vllm-openai:nightly-311b3513af33bc29b4acb2fde2e9313e5e9966a0}
     container_name: ${ERP_CONTAINER:-vllm-erp-seat}
     restart: unless-stopped
     ipc: host
@@ -31,6 +31,12 @@ services:
       - --tool-call-parser
       - gemma4
       - --enable-auto-tool-choice
+      # --reasoning-parser gemma4 + the enable_thinking pin are BOTH required (measured 2026-09-08):
+      # without them the post-tool-response turn leaks a literal "<|channel>thought\n<channel|>"
+      # prefix into content (3/3), exactly as stacks/gemma4-charrp/README.md warns. They do NOT
+      # fix forced (named) tool_choice — that failure is independent of the reasoning parser
+      # (measured 1/9 with it, 3/9 without): the model free-writes Gemma native call syntax
+      # instead of grammar-constrained JSON. See README for the forced-tool_choice status.
       - --reasoning-parser
       - gemma4
       - --default-chat-template-kwargs