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/opencode.js

@@ -1,6 +1,17 @@
+
 export default {
   "id": "opencode",
   "alias": "oc",
+  display: {
+      "name": "OpenCode Free",
+      "icon": "terminal",
+      "color": "#E87040",
+      "textIcon": "OC"
+  },
+  category: "free",
+  uiAlias: "oc",
+  noAuth: true,
+  passthroughModels: true,
   "transport": {
     "baseUrl": "https://opencode.ai",
     "headers": {
@@ -8,5 +19,10 @@ export default {
     },
     "noAuth": true
   },
+  media: {
+    noAuth: true,
+    passthroughModels: true,
+    modelsFetcher: { url: "https://opencode.ai/zen/v1/models", type: "opencode-free" }
+  },
   "models": []
 };