Add probe CLI improvements, D2H read, UCIe/HBM tuning, BW sweep

- Probe CLI: restructured output (tables first, routes below), per-hop
  timestamps, split cross-cube into best/worst cases, D2H read section
- UCIe overhead: 1ns -> 8ns per port (16ns per crossing) to fix
  cross-cube-best < cross-half latency inversion
- HBM efficiency: added efficiency=0.8 factor to hbm_ctrl, reducing
  effective BW from 256 to 204.8 GB/s
- Multi-size BW sweep: saturation tables (4KB-1MB) for all probe cases
- Probe default data size: 4KB -> 32KB for more realistic measurements
- IOChiplet NOC + D2H topology and tests
- NOC mesh, xbar, BW occupancy components and tests
- Cube mesh visualization diagram

278 tests pass.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/latency-model.md

@@ -44,9 +44,9 @@ This models arbitration, protocol processing, pipeline stages, etc.
 | fabric switch | 5.0 | Packet arbitration |
 | xbar | 2.0 | Crossbar arbitration |
 | xbar bridge | 1.0 | Bridge traversal between xbar halves |
-| ucie | 1.0 | UCIe protocol overhead per port |
+| ucie | 8.0 | UCIe protocol overhead per port (TX or RX; 16ns per crossing) |
 | noc (2D mesh) | 0.0 | Hop delay modeled internally via manhattan distance |
-| hbm_ctrl | 0.0 | Access time captured in drain_ns |
+| hbm_ctrl | 0.0 | Access time via drain_ns; efficiency=0.8 reduces edge BW (256→204.8) |
 | pe_cpu | 2.0 | Command dispatch |
 | pe_scheduler | 1.0 | PE-internal scheduling |
 | pe_gemm/math | 0.0 | Placeholder; will use flops-based model |