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/nanobanana.js

@@ -1,8 +1,24 @@
+
 export default {
   "id": "nanobanana",
   "alias": "nanobanana",
+  display: {
+      "name": "NanoBanana API",
+      "icon": "extension",
+      "color": "#FFD700",
+      "textIcon": "🍌",
+      "website": "https://nanobananaapi.ai",
+      "notice": {
+          "text": "3rd-party proxy for Google Nano Banana (Gemini 2.5/3 Flash Image). For official, use Gemini provider.",
+          "apiKeyUrl": "https://nanobananaapi.ai/dashboard"
+      }
+  },
+  category: "apikey",
+  uiAlias: "nb",
+  aliases: ["nb"],
   "transport": {
-    "baseUrl": "https://api.nanobananaapi.ai/v1/chat/completions"
+    "baseUrl": "https://api.nanobananaapi.ai/v1/chat/completions",
+    "validateUrl": "https://api.nanobananaapi.ai/v1/models"
   },
   "models": [
     {