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/registry/mmf.js

@@ -1,15 +1,17 @@
-
 export default {
-  "id": "mmf",  display: { name: "MMF", icon: "hub", color: "#6366F1", textIcon: "MF" },
-  category: "apikey",
-  "transport": {
-    "baseUrl": "https://api.xiaomimimo.com/api/free-ai/openai/chat",
-    "noAuth": true
+  id: "mmf",
+  display: {
+    name: "MMF",
+    icon: "hub",
+    color: "#6366F1",
+    textIcon: "MF",
   },
-  "models": [
-    {
-      "id": "mimo-auto",
-      "name": "MiMo Auto"
-    }
-  ]
+  category: "apikey",
+  transport: {
+    baseUrl: "https://api.xiaomimimo.com/api/free-ai/openai/chat",
+    noAuth: true,
+  },
+  models: [
+    { id: "mimo-auto", name: "MiMo Auto" },
+  ],
 };