Enhance benchmark: server power via IPMI, efficiency metrics, FP64, power limit check

- Sample server power (IPMI dcmi) during baseline+steady phases in parallel;
  compute delta vs GPU-reported sum; flag ratio < 0.75 as unreliable reporting
- Collect base_graphics_clock_mhz, multiprocessor_count, default_power_limit_w
  from nvidia-smi alongside existing GPU info
- Add tops_per_sm_per_ghz efficiency metric (model-agnostic silicon quality signal)
- Flag when enforced power limit is below default TDP by >5%
- Add fp64 profile to bee-gpu-burn worker (CUDA_R_64F, CUBLAS_COMPUTE_64F, min cc 8.0)
- Improve Executive Summary: overall pass count, FAILED GPU finding
- Throttle counters now shown as % of steady window instead of raw microseconds
- bible-local: clock calibration research, H100/H200 spec, real-world GEMM baselines

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

iso/builder/bee-gpu-stress.c

@@ -606,6 +606,20 @@ struct prepared_profile {
 };
 
 static const struct profile_desc k_profiles[] = {
+    {
+        "fp64",
+        "fp64",
+        80,
+        1,
+        0,
+        0,
+        8,
+        CUDA_R_64F,
+        CUDA_R_64F,
+        CUDA_R_64F,
+        CUDA_R_64F,
+        CUBLAS_COMPUTE_64F,
+    },
     {
         "fp32_tf32",
         "fp32",