[Klaud Cold][agentic experiment][Variant D] Kimi-K3 B200 agg TP8xPP2 agentic — direct vllm serve (srt-slurm PR 278) / Kimi-K3 B200 聚合式 TP8xPP2 智能体实验——直接 vllm serve（srt-slurm PR 278） - #2359

This recipe is the first to pair the shared `agentic_srt.sh` inter-concurrency drain wait (which polls for the Dynamo-only metric `dynamo_frontend_active_requests`) with a no-Dynamo, direct-`vllm serve` frontend that never emits it, so the idle check is vacuously true from the first poll. It's dormant today because `conc-list` is a single point `[8]` (the drain wait only runs between points), but the recipe's own comment says the curve will be widened later — at that point later concurrency poin

The launcher's pre-existing sed at runners/launch_b200-dgxc.sh:300 (`sed -i 's/^  max_attempts: [0-9]*/  max_attempts: 720/'`) unconditionally rewrites this recipe's `health_check.max_attempts: 1440` (4h) down to 720 (2h) before every `srtctl apply`, since the recipe line matches the 2-space-indent regex. This is pre-existing launcher behavior surfaced by this PR's recipe, not a bug the PR introduces — and in this specific recipe it's inert since `VLLM_ENGINE_READY_TIMEOUT_S: 3600` (1h) already