docs: regenerate the traceability matrix for VR-014

The committed matrix predated the audio-signature binding, so VR-014 and
the four UT tags in `test_audio_offset.py` were absent from it while being
present in the register — the one inconsistency a generated file is
supposed to make impossible.

VR-014 also needed an explicit tier row. The blanket `VR-* | Out of CI`
line is right about every other study and wrong about this one: its
fixture is committed and its signature is CPU-only DSP, so it is a test a
CI host can run rather than a measurement someone has to remember to
repeat. Left as an exception under the blanket rather than rewriting the
rule, because the rule still describes the other thirteen.

Coverage unchanged at 38/69; the gate reports no orphan tags.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

TRACES: VR-014

docs/requirements.md

@@ -213,6 +213,7 @@ as such rather than counted as covered.
 | GR-001 … GR-005 | T1 + T3 | Gallery assembly is I/O and bookkeeping; embedding is T3 smoke |
 | GR-006 … GR-008 | T1 | Tiering and outlier detection operate on stored embeddings |
 | VR-* | Out of CI | Studies are run deliberately and their results committed as documents |
+| VR-014 | **T2** | The exception, and the reason the blanket row above is not the whole story: its fixture is committed and its signature is CPU-only DSP, so the study *is* a test a CI host can run — not a measurement someone has to remember to repeat |
 
 **One consequence worth stating:** AR-027 (arbitrary gallery scale) is
 structurally unverifiable on the CI host. It needs a GPU host and a synthetic