agentx: kimik2.7 full-sweep search-space + perf-changelog

Set the kimik2.7-fp4-mi355x-vllm-agentic sweep to conc [1,4,8,16,32,48] for
both none and dram/LMCache at TP4, dram-utilization 0.80. Add the corresponding
perf-changelog entry (pr-link placeholder to fill on PR open).

Author: hyukjlee

configs/amd-master.yaml

@@ -820,8 +820,8 @@ kimik2.7-fp4-mi355x-vllm-agentic:
     agentic-coding:
     - dram-utilization: 0.80
       search-space:
-      - { tp: 4, kv-offloading: none, conc-list: [32, 64] }
-      - { tp: 4, kv-offloading: dram, kv-offload-backend: lmcache, conc-list: [32, 64] }
+      - { tp: 4, kv-offloading: none, conc-list: [1, 4, 8, 16, 32, 48] }
+      - { tp: 4, kv-offloading: dram, kv-offload-backend: lmcache, conc-list: [1, 4, 8, 16, 32, 48] }
 
 
 kimik2.5-fp4-mi355x-atom: