feat(ui): expose diarization models over the typed api (FR-MODEL-1)

src/lib/api.ts

@@ -413,10 +413,15 @@ export const api = {
   downloadNpuPackage: () => invoke<void>("download_npu_package"),
   downloadDirectmlPackage: () => invoke<void>("download_directml_package"),
   listModels: () => invoke<ModelInfo[]>("list_models"),
+  // The fixed segmentation+embedding pair that speaker diarization needs
+  // installed before it can separate speakers (T4.7, FR-MODEL-1). Same
+  // ModelInfo shape as whisper models; download via `downloadModel` with the
+  // `diar-seg`/`diar-emb` kind, remove via the shared `removeModel`.
+  listDiarizationModels: () => invoke<ModelInfo[]>("list_diarization_models"),
   // T8.7/FR-TRX-4: static catalog of whisper.cpp-recognized language codes
   // for the Settings dropdown; "Auto-detect" is a frontend-only addition.
   listWhisperLanguages: () => invoke<LanguageOption[]>("list_whisper_languages"),
-  downloadModel: (id: string, kind: "whisper" = "whisper") =>
+  downloadModel: (id: string, kind: "whisper" | "diar-seg" | "diar-emb" = "whisper") =>
     invoke<void>("download_model", { args: { kind, id } }),
   removeModel: (id: string) => invoke<void>("remove_model", { id }),
   // `language` (T8.7): omit/undefined reuses whatever language the meeting