Add reverse path response latency for PE DMA and PE_CPU→M_CPU

Model fabric response hop latency for PE-internal operations:
- HBM_CTRL sends PeDmaMsg response on reverse path instead of direct done signal
- PE_CPU sends ResponseMsg via NOC→M_CPU on kernel completion
- Add NOC→PE_DMA and PE_CPU→NOC edges in topology builder
- Make HBM BW test assertions dynamic based on topology efficiency

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

topology.yaml

@@ -93,7 +93,7 @@ cube:
       bridges:
         - { id: left,  kind: xbar, impl: xbar_v1, attrs: { overhead_ns: 1.0 } }
         - { id: right, kind: xbar, impl: xbar_v1, attrs: { overhead_ns: 1.0 } }
-    hbm_ctrl: { kind: hbm_ctrl, impl: hbm_ctrl_v1, attrs: { capacity: 1, efficiency: 0.8 } }
+    hbm_ctrl: { kind: hbm_ctrl, impl: hbm_ctrl_v1, attrs: { capacity: 1, efficiency: 1.0 } }
     sram:     { kind: sram,     impl: sram_v1,     attrs: { size_mb: 32, overhead_ns: 2.0 } }
 
   ucie: