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>

tests/test_phase_a_components.py

@@ -24,7 +24,6 @@ from kernbench.components.builtin import (
     IoCpuComponent,
     MCpuComponent,
     PcieEpComponent,
-    PositionAwareXbarComponent,
     SramComponent,
     TransitComponent,
 )
@@ -232,7 +231,6 @@ def test_m_cpu_terminal_no_ctx_completes():
     ("forwarding_v1", TransitComponent),
     ("noc_v1",        TransitComponent),
     ("ucie_v1",       TransitComponent),
-    ("xbar_v1",       PositionAwareXbarComponent),
     ("pcie_ep_v1",    PcieEpComponent),
     ("io_cpu_v1",     IoCpuComponent),
     ("m_cpu_v1",      MCpuComponent),