fix(pcie): verify GPU links under real bandwidth load

bible-local/architecture/api-surface.md

@@ -41,7 +41,7 @@ All SAT run endpoints enqueue an async task. Response: `{"task_id": "..."}`.
 | POST   | `/api/sat/nvidia-targeted-power/run`       | NVIDIA targeted power             |
 | POST   | `/api/sat/nvidia-pulse/run`                | NVIDIA pulse test                 |
 | POST   | `/api/sat/nvidia-interconnect/run`         | NCCL all_reduce_perf              |
-| POST   | `/api/sat/nvidia-bandwidth/run`            | NVBandwidth test                  |
+| POST   | `/api/sat/nvidia-bandwidth/run`            | NVBandwidth + PCIe link under load |
 | POST   | `/api/sat/nvidia-stress/run`               | NVIDIA stress pack                |
 | POST   | `/api/sat/memory/run`                      | Memory acceptance                 |
 | POST   | `/api/sat/storage/run`                     | Storage acceptance (smartctl)     |

bible-local/architecture/runtime-flows.md

@@ -285,12 +285,12 @@ Web UI: Acceptance Tests page -> Run Test button
 Web UI: "Run All" button -> POST /api/sat/run-all
   body: operator intent only { stress_mode, amd_targets[], nvidia_gpu_indices[] }
   server (handler.planSATRunAll):
-    1. always: cpu, memory, storage, pcie-link
+    1. always: cpu, memory, storage
     2. tpm            - only if App.TPMPresent() finds tpm_version_major=2
     3. nvidia-config  - if DetectGPUPresence().Nvidia || NvidiaInitializing
     4. wait for NVIDIA enumeration: repeat fresh ListNvidiaGPUs queries until
        at least one GPU is returned, NvidiaGSPMode=="gsp-stuck", or 75s
-    5. nvidia / nvidia-interconnect / nvidia-bandwidth / nvidia-pcie-bandwidth
+    5. nvidia / nvidia-interconnect / nvidia-bandwidth
        (+ targeted-stress/power/pulse when stress_mode) - only once ready,
        -i = App.ListNvidiaGPUs() indices (intersected with the requested subset)
     6. amd / amd-mem / amd-bandwidth - if DetectGPUPresence().AMD and selected
@@ -306,6 +306,9 @@ Web UI: "Run All" button -> POST /api/sat/run-all
   vendor detection plus an lspci display-class fallback).
   `/api/gpu/presence`, `/api/gpu/tools` and the planner all use it.
 - `bee-gpu-burn` / `bee-john-gpu-stress` use `exec.CommandContext`: killed on job context cancel.
+- `nvidia-bandwidth` samples every selected GPU's negotiated PCIe speed and
+  width immediately after its final all-GPU `dcgmi diag -r nvbandwidth`
+  command exits. Idle and forced-retrain readings are not health verdicts.
 - Metric goroutine uses stopCh/doneCh pattern; main goroutine waits `<-doneCh` before reading rows (no mutex needed).
 - SVG chart is fully offline: no JS, no external CSS, pure inline SVG.
 - `RunNvidiaBandwidthPack` runs one all-GPU `nvbandwidth` pass in Validate; the