refactor(open-sse): B1 consolidate media endpoint URLs into registry

- image/embed/tts/search base URLs derive from media.*Config.baseUrl /
  searchViaChat.endpoint (single source); handlers read PROVIDER_MEDIA.
- ~18 hardcoded endpoints moved: bfl/fal/stability/runway/hf/gemini/
  cloudflare/recraft/sdwebui/comfyui/nanobanana image, voyage embed,
  gemini/openrouter tts, chatSearch endpoints.
- Byte-identical: PROVIDERS 62 + alias 90 baselines, image buildUrl outputs.

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

open-sse/providers/registry/stability-ai.js

@@ -17,6 +17,10 @@ export default {
   authType: "apikey",
   aliases: ["stability"],
   "transport": null,
+  media: {
+    serviceKinds: ["image"],
+    imageConfig: { baseUrl: "https://api.stability.ai/v2beta/stable-image/generate" }
+  },
   "models": [
     {
       "id": "stable-image-ultra",