Move bridged TC off the node NIC so the DUT can own its qdisc

[Jafaral]

• Host-to-switch delay / rate / loss are applied on the switch, not the node NIC, so the DUT keeps its root qdisc.
• Switch to: N is traffic toward that node (node RX, switch egress). Switch from: N is traffic from that node (node TX, IFB on switch ingress). Use two entries for both directions.
• A node’s own delay still means that node’s TX (same pipe as from:). Network-root constraints still default to to: (RX). P2P is unchanged; warn if TC stays on the node.

Example Config

networks:
  - name: wan1
    connections:
      - to: r1
        delay: 2500
        rate: { rate: "15M", burst: 16384, limit: 131072 }
      - from: r1
        delay: 2500
        rate: { rate: "15M", burst: 16384, limit: 131072 }