Record CPU VAD build and audited timestamp failure traps

docs/SPEECH-VAD.md

@@ -141,7 +141,37 @@ and publication; reject stale output. Persist provenance and explicit completion
 or no-speech status. Foreground search must remain usable while ASR is pending;
 an already executing encode cannot be claimed preemptible on a one-thread budget.
 
-Open gates: native VAD build, actual one-thread audit, detection/recognition
+## Local diagnostic build and protocol audit
+
+The standalone `whisper-vad-speech-segments` Release target built successfully
+on Windows on 2026-10-13 from the pinned commit above, with one build job.
+Its executable SHA-256 is
+`2b18297bad2ea6c87fa9f314364069b74480a6c916fa8da06fe4c8ad40c9abf6`.
+The inspected CMake cache has `BUILD_SHARED_LIBS`, `GGML_BACKEND_DL`,
+`GGML_CUDA`, `GGML_VULKAN`, and `GGML_METAL` all OFF. This is an internal
+CPU diagnostic, not a replacement for the product's hardware-detecting runtime.
+Upstream C4244 and C4267 conversion warnings remain. No detection was run.
+
+Source review identified further requirements before accepting measurements:
+
+- Stdout interval values are rounded integer centiseconds printed with float
+  formatting. Multiply by ten for milliseconds; stderr instead shows seconds.
+- The last inference frame is zero-padded. Its interval may exceed real audio
+  length. Preserve the raw interval and explicitly record its intersection with
+  verified source samples; do not silently clamp the evidence.
+- The 30-ms speech padding is already applied. Do not apply it twice. The
+  segmentation implementation also merges gaps below 200 ms; the overlap
+  parameter does not add overlap to standalone intervals.
+- A graph computation failure can break detection while the API still returns
+  true. Probability storage is preallocated, so count and finite values alone
+  cannot establish completion. Capture error-level native logs and invalidate
+  the run on errors before using any intervals.
+- Unknown or incomplete standalone CLI arguments can exit successfully. A
+  successful exit alone is insufficient. A diagnostic wrapper should fix CPU
+  mode and one thread, check segment allocation, retain probabilities and
+  separate model loading, detection and segmentation timings.
+
+Open gates: actual one-thread audit, detection/recognition
 comparison, ordinary and DTW timestamp regression, independent held-out quality,
 background starvation/cancellation/crash recovery, packaging/license review,
 native OS and physical GPU fallback. None is closed by this research document.