Validate gated Google retrieval and record unchanged localization quality

docs/ROADMAP.md

@@ -82,6 +82,9 @@ release. Keep their evidence and unchecked production gates intact.
   - [x] Build a pinned CPU VAD diagnostic with explicit one-thread inference,
     native error detection and full probabilities; actual Silero silence/input
     contracts passed. Media quality comparison remains open (see SPEECH-VAD.md).
+  - [x] Complete frozen five-source VAD/base-ASR/Google CPU diagnostic:
+    component costs decreased, but localization stayed 4/8 point and 6/8 overlap;
+    no production default selected. Independent held-out media quality remains open.
   - [ ] Run genuine local speech candidates, Google transcript retrieval and
     held-out English/German/music/no-speech checks before selecting a default.
 - [ ] Package and verify decoders on every release OS; test production acceleration.