feat(qoder): port Kiro-style provider integration with COSY signing

Replaces the Qoder placeholder with a real free-tier provider:

- Device-flow OAuth: PKCE + nonce generated locally, user authorizes at
  qoder.com/device/selectAccounts, poll openapi.qoder.sh until token
- COSY signing (RSA-1024 + AES-128-CBC + MD5) for chat / model-list
- WAF-bypass body encoding (custom-alphabet base64 + thirds rearrange)
- Live model_config catalog from /algo/api/v2/model/list, cached 1h
- 11 models registered (auto/ultimate/performance/efficient/lite +
  6 frontier *model ids)
- Usage fetcher for openapi.qoder.sh/api/v2/quota/usage
- Dashboard live-models resolver, provider test, OAuth modal hookup
- 24 unit tests covering encoder, PKCE, COSY headers, sigPath stripping

src/app/api/providers/[id]/models/route.js

@@ -5,6 +5,7 @@ import { GEMINI_CONFIG } from "@/lib/oauth/constants/oauth";
 import { refreshGoogleToken, updateProviderCredentials } from "@/sse/services/tokenRefresh";
 import { resolveOllamaLocalHost } from "open-sse/config/providers.js";
 import { resolveKiroModels } from "open-sse/services/kiroModels.js";
+import { resolveQoderModels } from "open-sse/services/qoderModels.js";
 
 const GEMINI_CLI_MODELS_URL = "https://cloudcode-pa.googleapis.com/v1internal:fetchAvailableModels";
 
@@ -286,6 +287,41 @@ const PROVIDER_MODELS_CONFIG = {
       return { models: [], warning };
     }
   },
+  qoder: {
+    customResolver: async (connection) => {
+      const credentials = {
+        accessToken: connection.accessToken,
+        refreshToken: connection.refreshToken,
+        email: connection.email,
+        displayName: connection.displayName,
+        providerSpecificData: connection.providerSpecificData || {},
+      };
+      let warning;
+      try {
+        const result = await resolveQoderModels(credentials, { forceRefresh: true });
+        if (result?.models?.length) {
+          return {
+            models: result.models.map((m) => ({
+              // Use the canonical "qoder/<key>" id so the dashboard
+              // surfaces the same identifier the chat router expects.
+              id: `qoder/${m.id}`,
+              name: m.name,
+              contextLength: m.contextLength,
+              isVL: m.isVL,
+              isReasoning: m.isReasoning,
+              maxOutputTokens: m.maxOutputTokens,
+              description: m.description,
+            })),
+          };
+        }
+        warning = "Qoder returned no models; falling back to static catalog.";
+      } catch (error) {
+        warning = `Failed to fetch Qoder models: ${error.message}`;
+        console.log("Failed to fetch Qoder models dynamically, falling back to static:", error.message);
+      }
+      return { models: [], warning };
+    },
+  },
   "gemini-cli": {
     customResolver: buildOAuthResolver({
       refreshFn: (conn) => refreshGoogleToken(conn.refreshToken, GEMINI_CONFIG.clientId, GEMINI_CONFIG.clientSecret),

src/app/api/providers/[id]/test/testUtils.js

@@ -61,6 +61,15 @@ const OAUTH_TEST_CONFIG = {
   },
   qwen: { checkExpiry: true, refreshable: true },
   kiro: { checkExpiry: true, refreshable: true },
+  qoder: {
+    // Test by hitting Qoder's userinfo endpoint with the device token.
+    url: "https://openapi.qoder.sh/api/v1/userinfo",
+    method: "GET",
+    authHeader: "Authorization",
+    authPrefix: "Bearer ",
+    checkExpiry: true,
+    refreshable: false,
+  },
   "kimi-coding": { checkExpiry: true, refreshable: false },
   cursor: { tokenExists: true },
   kilocode: {