Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/migrations/227_composite_routes_add_cn_providers.sql

@@ -0,0 +1,8 @@
+-- Allow Composite model routes to target the three concrete CN providers.
+ALTER TABLE composite_model_routes
+    DROP CONSTRAINT IF EXISTS composite_model_routes_target_platform_check;
+
+ALTER TABLE composite_model_routes
+    ADD CONSTRAINT composite_model_routes_target_platform_check
+    CHECK (target_platform IN ('anthropic', 'openai', 'gemini', 'antigravity', 'grok',
+                               'kimi', 'zhipu', 'deepseek'));