refactor(open-sse): registry consolidation + DRY media/oauth/adhoc cleanup

- Single-source registry: oauth clientId/tokenUrl, usage URLs, image/embed
  configs, search defaultModel, codex fixedPort, google token url derive.
- Remove 29 unused OmniRoute providers (registry 100→71); media intact.
- De-adhoc: codex literals → registry format/oauth flags; reasoningInject,
  image/embed openrouter headers + xai bodyFields config-driven.
- Add REGISTRY_TEMPLATE.js + expand PROVIDER_DEFAULTS/schema JSDoc.
- Baselines updated; PROVIDERS 62 + alias 90 byte-for-byte, golden snapshots.

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

open-sse/providers/registry/vercel-ai-gateway.js

@@ -1,10 +1,36 @@
+
 export default {
   "id": "vercel-ai-gateway",
   "alias": "vercel-ai-gateway",
+  display: {
+      "name": "Vercel AI Gateway",
+      "icon": "deployed_code",
+      "color": "#111827",
+      "textIcon": "VG",
+      "website": "https://vercel.com/ai-gateway",
+      "notice": {
+          "text": "Unified OpenAI-compatible endpoint from Vercel. Use your AI Gateway API key, then pick models with provider/model IDs like anthropic/claude-sonnet-4.6 or openai/gpt-5.4.",
+          "apiKeyUrl": "https://vercel.com/dashboard/~/ai-gateway"
+      }
+  },
+  category: "apikey",
+  uiAlias: "vercel",
+  passthroughModels: true,
+  aliases: ["vercel"],
   "transport": {
     "baseUrl": "https://ai-gateway.vercel.sh/v1/chat/completions",
     "retry": {
       "429": 2
-    }
-  }
+    },
+    usage: { url: "https://ai-gateway.vercel.sh/v1/credits" }
+  },
+  media: {
+    serviceKinds: ["llm", "embedding", "image", "imageToText", "webSearch"],
+    searchViaChat: { defaultModel: "openai/gpt-4o-mini", pricingUrl: "https://vercel.com/docs/ai-gateway/pricing" },
+    modelsFetcher: { url: "https://ai-gateway.vercel.sh/v1/models", type: "openai" },
+    imageConfig: { baseUrl: "https://ai-gateway.vercel.sh/v1/images/generations" },
+    embeddingConfig: { baseUrl: "https://ai-gateway.vercel.sh/v1/embeddings" },
+    passthroughModels: true
+  },
+  features: {"usage":true,"usageApikey":true},
 };