refactor(registry): B2 migrate to LiteLLM-style schema — unified models[] with kind field

- 71 registry files: flat `media.*Config.models` → `models[]` with `kind` field
- `media` wrapper removed → serviceKinds, *Config fields promoted top-level
- `type` field renamed to `kind` (llm/image/tts/stt/embedding/embedding/video/music)
- providers/index.js: PROVIDER_MEDIA now built from flat top-level media fields
- shared/constants/providers.js: buildProviderEntry reads flat top-level media fields
- route /v1/models: modelKind() uses kind||type; removed subConfig merge block
- models/info route: removed sub-config fallback lookup (all models in PROVIDER_MODELS)
- ttsProviders/index.js: synthesizeViaConfig reads tts models from PROVIDER_MODELS
- test-models route, helpers.js, validate route: kind||type compat
- Baselines: PROVIDERS 62/62 ✅, Alias 90/90 ✅

Co-authored-by: Cursor <cursoragent@cursor.com>

open-sse/providers/models/helpers.js

@@ -3,7 +3,7 @@ export const CODEX_REVIEW_SUFFIX = "-review";
 
 export function withCodexReviewModels(models) {
   return models.flatMap((model) => {
-    if ((model.type || "llm") !== "llm" || model.id.endsWith(CODEX_REVIEW_SUFFIX)) {
+    if ((model.kind || model.type || "llm") !== "llm" || model.id.endsWith(CODEX_REVIEW_SUFFIX)) {
       return [model];
     }
     return [