Allow async streamFn for dynamic proxy settings

- StreamFn type now allows returning Promise
- agent-loop awaits streamFn result
- createStreamFn takes getProxyUrl callback, reads settings on each call

packages/agent/src/agent-loop.ts

@@ -211,7 +211,7 @@ async function streamAssistantResponse(
 	const resolvedApiKey =
 		(config.getApiKey ? await config.getApiKey(config.model.provider) : undefined) || config.apiKey;
 
-	const response = streamFunction(config.model, llmContext, {
+	const response = await streamFunction(config.model, llmContext, {
 		...config,
 		apiKey: resolvedApiKey,
 		signal,

packages/agent/src/types.ts

@@ -11,7 +11,10 @@ import type {
 } from "@mariozechner/pi-ai";
 import type { Static, TSchema } from "@sinclair/typebox";
 
-export type StreamFn = typeof streamSimple;
+/** Stream function - can return sync or Promise for async config lookup */
+export type StreamFn = (
+	...args: Parameters<typeof streamSimple>
+) => ReturnType<typeof streamSimple> | Promise<ReturnType<typeof streamSimple>>;
 
 /**
  * Configuration for the agent loop.