feat(ai): add Radius gateway support

packages/ai/src/compat.ts

@@ -19,6 +19,7 @@ export * from "./api/mistral-conversations.lazy.ts";
 export * from "./api/openai-codex-responses.lazy.ts";
 export * from "./api/openai-completions.lazy.ts";
 export * from "./api/openai-responses.lazy.ts";
+export * from "./api/pi-messages.lazy.ts";
 export * from "./env-api-keys.ts";
 export * from "./image-models.ts";
 export * from "./images.ts";
@@ -36,8 +37,12 @@ import { mistralConversationsApi } from "./api/mistral-conversations.lazy.ts";
 import { openAICodexResponsesApi } from "./api/openai-codex-responses.lazy.ts";
 import { openAICompletionsApi } from "./api/openai-completions.lazy.ts";
 import { openAIResponsesApi } from "./api/openai-responses.lazy.ts";
+import { piMessagesApi } from "./api/pi-messages.lazy.ts";
 import { getEnvApiKey } from "./env-api-keys.ts";
 import { builtinModels, getBuiltinModel, getBuiltinModels, getBuiltinProviders } from "./providers/all.ts";
+
+export type { BuiltinProvider } from "./providers/all.ts";
+
 import { createFauxCore, type FauxProviderRegistration, type RegisterFauxProviderOptions } from "./providers/faux.ts";
 import type {
 	Api,
@@ -179,6 +184,7 @@ const BUILTIN_APIS: [Api, ProviderStreams][] = [
 	["google-vertex", googleVertexApi()],
 	["mistral-conversations", mistralConversationsApi()],
 	["bedrock-converse-stream", bedrockConverseStreamApi()],
+	["pi-messages", piMessagesApi()],
 ];
 
 const builtinApiProviderInstances = new Map<Api, ReturnType<typeof getApiProvider>>();