feat(api-ai): add provider registry and routing fallback

apps/api/src/ai/ai.module.ts

@@ -0,0 +1,14 @@
+import { Module } from "@nestjs/common";
+import { PrismaModule } from "../prisma/prisma.module";
+import { AiController } from "./ai.controller";
+import { AiProviderRegistryService } from "./ai-provider-registry.service";
+import { AiService } from "./ai.service";
+import { AstrbotProvider } from "./providers/astrbot.provider";
+import { OpenAiCompatibleProvider } from "./providers/openai-compatible.provider";
+
+@Module({
+  imports: [PrismaModule],
+  controllers: [AiController],
+  providers: [AiService, AiProviderRegistryService, OpenAiCompatibleProvider, AstrbotProvider]
+})
+export class AiModule {}