docs: measured PP link math (H=5120 verified, 20.5 MB/ubatch wire), NIC inventory

- Ethernet Bandwidth Math: new section 0 with live measurements
  (iperf 281-294 MB/s, ping RTT both paths, prefill 457.9 t/s at
  2.5GbE, per-ubatch wire 20.5 MB, 98k KV snapshot 3.45 GB blocking
  the slot 13.6 s, validated link-speed model: 386/458/505 t/s)
- System specs: NIC tables for both boxes; the 1 GbE USB-C adapter on
  the claw was silently routing the RPC path (unplugged 2026-08-17)
- PP Deployment: fix hidden-state size (10 KiB/direction, H=5120) and
  RTT-vs-bandwidth claim (decode RTT-bound; prefill+snapshot BW-bound)

docs/Pipeline Parallelism/Qwen3.8 PP Deployment.md

@@ -132,14 +132,21 @@ Dankclaw (head, 192.168.0.143)          Dankserver (worker, 192.168.0.235)
 llama-server b10433                      ggml-rpc-server b10433
   --rpc 192.168.0.235:50052                 --host 192.168.0.235 --port 50052
   model file (31.5 GB)                     -d CUDA0 -c (tensor cache)
-  [RPC0, ROCm0|Vulkan0]  layers            RTX 3090: layers 0..~31
-  Strix:    layers ~32..64 + lm_head
-  hidden state ~20 KiB crosses the link once per token, each direction
+  [RPC0, ROCm0|Vulkan0]  layers            RTX 3090: layers 0-44 (45 of 65 blocks)
+  Strix:    layers 45-64 + lm_head
+  hidden state 10 KiB/position/direction (H=5120, GGUF-verified);
+  measured wire bytes ~40 KB/position/direction (serialized graph
+  dominates); 20.5 MB per ubatch both directions. Details:
+  [[Ethernet Bandwidth Math]] section 0.
 ```
 
 - **Layer-sequential split** (true pipeline parallelism): layers 0..N run on
   the worker, the rest on the head, in order. One hidden-state handoff per
-  token step. RTT-bound, not bandwidth-bound.
+  token step. DECODE is RTT-bound, not bandwidth-bound (network is ~1-2.5%
+  of step time). PREFILL and the prompt-cache KV snapshot ARE
+  bandwidth-bound: the link runs at line rate for the wire burst of every
+  ubatch and ~100% during the snapshot copy. Measured numbers:
+  [[Ethernet Bandwidth Math]] section 0.
 - **Why the head is on Dankclaw:** the model file is already there; the
   worker streams its tensor share at load (no 31.5 GB copy to the server).
 - **Both sides must run the identical build** (b10433 / 9b05354ec). The