feat: complete remaining Go backend modules

contracts/providers/http-v1.json

@@ -0,0 +1,12 @@
+{
+  "version": 1,
+  "providers": {
+    "volcengine-visual": {"submitAction": "CVSync2AsyncSubmitTask", "queryAction": "CVSync2AsyncGetResult", "auth": "HMAC-SHA256"},
+    "evolink": {"submit": "/v1/images/generations", "query": "/v1/tasks/{id}", "auth": "bearer"},
+    "bailian": {"imageSubmit": "/api/v1/services/aigc/image-generation/generation", "videoSubmit": "/api/v1/services/aigc/video-generation/video-synthesis", "query": "/api/v1/tasks/{id}", "auth": "bearer"},
+    "seedance": {"submit": "/contents/generations/tasks", "query": "/contents/generations/tasks/{id}", "auth": "bearer"},
+    "mock": {"deterministic": true}
+  },
+  "errors": {"generic": true, "secretSafe": true},
+  "liveCallsInTests": false
+}