test(gallery): expect speaker_recognition on the bundles with a voice component

The parakeet-cpp backend now answers VoiceEmbed and VoiceVerify, so the
pinning test asserts the usecase on the entries that declare it instead of
its absence. Document voice_verify_threshold.

Assisted-by: Claude Code:claude-sonnet-5-5

core/gallery/parakeet_bundle_entries_test.go

@@ -65,18 +65,15 @@ var _ = Describe("gallery/index.yaml parakeet-cpp bundle entries", func() {
 		}
 	})
 
-	// speaker_recognition is deliberately absent: that usecase means the model
-	// answers the /v1/voice/* RPCs (VoiceEmbed, VoiceVerify), which the
-	// parakeet-cpp backend does not implement, and it picks the default model
-	// for those routes. Naming registered speakers works from the
-	// speaker_component option alone, with no usecase.
+	// speaker_recognition means the model answers the /v1/voice/* RPCs
+	// (VoiceEmbed, VoiceVerify). The parakeet-cpp backend does since it binds
+	// parakeet_capi_speaker_embed_pcm, so entries with a speaker encoder declare it.
 	It("declares the usecases and options of the roles each bundle covers", func() {
 		all := entries()
 		for name, w := range want {
 			e := all[name]
 			Expect(e.Overrides["known_usecases"]).To(ConsistOf(toAny(w.usecases)...), name)
 			Expect(e.Overrides["options"]).To(ConsistOf(toAny(w.options)...), name)
-			Expect(e.Overrides["known_usecases"]).ToNot(ContainElement("speaker_recognition"), name)
 		}
 	})
 

docs/content/features/voice-recognition.md

@@ -230,6 +230,9 @@ other. Use a distance threshold near 0.5 for this encoder, as for `speaker_model
 naming below. The response `model` field is the `sha256:` identity of the encoder
 weights.
 
+`/v1/voice/verify` uses a distance threshold of 0.5 when the request has none. Set the
+model option `voice_verify_threshold:<distance>` (a distance in (0, 2)) to change it.
+
 Only embedding, identification and plain verification are available. There is no
 anti-spoofing head, so a verify request with `anti_spoofing: true` is refused, and
 `/v1/voice/analyze` is not served by parakeet-cpp. The backend needs a libparakeet.so