fix(agentic): extend warmup drain timeout (#2243)

Increase the AgentX warmup grace period from 10 minutes to 30 minutes so long-context requests can drain before profiling.

中文：将 AgentX 预热排空等待时间从 10 分钟延长至 30 分钟，确保长上下文请求在正式性能采集前完成。

Author: cquil11

benchmarks/benchmark_lib.sh

@@ -1479,9 +1479,9 @@ build_replay_cmd() {
     # with one-token outputs and no idle delays for 10 minutes. Profiling begins
     # only after those requests drain and resumes from the resulting live state.
     REPLAY_CMD+=" --agentic-cache-warmup-duration 600"
-    # Give long-context warmup requests up to 10 minutes to drain before
+    # Give long-context warmup requests up to 30 minutes to drain before
     # cancelling any remaining requests and starting profiling.
-    REPLAY_CMD+=" --warmup-grace-period 600"
+    REPLAY_CMD+=" --warmup-grace-period 1800"
     # Use server-reported usage fields (prompt_tokens / completion_tokens) for
     # ISL/OSL instead of client-side tokenizer.encode(). Auto-enables
     # stream_options.include_usage on the OpenAI chat endpoint. Skips the