Remove xbar/noc remnants, rule-based cube-view connectors

- Delete xbar.py and noc.py (TwoDMeshNocComponent) — unused since router mesh
- Remove xbar_v1/noc_2d_mesh_v1 from components.yaml
- Fix pe_to_xbar → pe_to_router in routing exclusion set
- Fix xbar_to_hbm_bw_gbs → hbm_to_router_bw_gbs in report.py
- Update all docstrings/comments referencing xbar/bridge → router mesh
- Cube-view connectors: rule-based _connector_points helper
  - PE↔router: single diagonal line (not chevron)
  - UCIe N/S: 45°→horizontal→45°
  - UCIe E/W: 45°→vertical→45°
  - HBM ports: 45°→horizontal→45°

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

src/kernbench/sim_engine/event_log.py

@@ -287,7 +287,7 @@ def _generate_probe_d2h(graph, edge_map) -> list[dict]:
 
 
 def _generate_probe_pe_dma(graph, edge_map) -> list[dict]:
-    """PE DMA probes: pe_dma → xbar → HBM."""
+    """PE DMA probes: pe_dma → router mesh → HBM."""
     from kernbench.policy.address.phyaddr import PhysAddr
     from kernbench.policy.routing.router import AddressResolver, PathRouter