refactor(open-sse): P3 provider registry — split into providers/registry/{id}.js

- 100 registry files: transport + models co-located per provider (Mongoose-style)
- providers/shared.js: shared Claude headers + OS/arch helpers (deduped)
- providers/models/helpers.js: withCodexReviewModels (kept dynamic)
- providers/index.js builds PROVIDERS + PROVIDER_MODELS = old API (content byte-for-byte)
- config/providers.js + providerModels.js → barrel re-export, keep accessors + runtime helpers
- Verified: PROVIDERS/MODELS/OAuth/alias byte-for-byte, golden translator tests pass, 0 new regression

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

open-sse/providers/registry/qwen.js

@@ -0,0 +1,28 @@
+export default {
+  "id": "qwen",
+  "alias": "qw",
+  "transport": {
+    "baseUrl": "https://portal.qwen.ai/v1/chat/completions",
+    "clientId": "f0304373b74a44d2b584a3fb70ca9e56",
+    "tokenUrl": "https://chat.qwen.ai/api/v1/oauth2/token",
+    "authUrl": "https://chat.qwen.ai/api/v1/oauth2/device/code"
+  },
+  "models": [
+    {
+      "id": "qwen3-coder-plus",
+      "name": "Qwen3 Coder Plus"
+    },
+    {
+      "id": "qwen3-coder-flash",
+      "name": "Qwen3 Coder Flash"
+    },
+    {
+      "id": "vision-model",
+      "name": "Qwen3 Vision Model"
+    },
+    {
+      "id": "coder-model",
+      "name": "Qwen3.6 Coder Model"
+    }
+  ]
+};