chore(vendor): import pi 0.85.1

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: d981de1229ef899957bbe968bc8dcda02a21f477

third_party/pi/packages/ai/src/providers/images/register-builtins.ts

@@ -0,0 +1,50 @@
+import type { generateImages as generateImagesOpenRouterFunction } from "../../api/openrouter-images.ts";
+import { registerImagesApiProvider } from "../../images-api-registry.ts";
+import type { AssistantImages, ImagesContext, ImagesFunction, ImagesModel, ImagesOptions } from "../../types.ts";
+
+interface OpenRouterImagesProviderModule {
+	generateImages: typeof generateImagesOpenRouterFunction;
+}
+
+let openRouterImagesProviderModulePromise: Promise<OpenRouterImagesProviderModule> | undefined;
+
+function createLazyLoadErrorImages(model: ImagesModel<"openrouter-images">, error: unknown): AssistantImages {
+	return {
+		api: model.api,
+		provider: model.provider,
+		model: model.id,
+		output: [],
+		stopReason: "error",
+		errorMessage: error instanceof Error ? error.message : String(error),
+		timestamp: Date.now(),
+	};
+}
+
+function loadOpenRouterImagesProviderModule(): Promise<OpenRouterImagesProviderModule> {
+	openRouterImagesProviderModulePromise ||= import("../../api/openrouter-images.ts").then(
+		(module) => module as OpenRouterImagesProviderModule,
+	);
+	return openRouterImagesProviderModulePromise;
+}
+
+export const generateImagesOpenRouter: ImagesFunction<"openrouter-images", ImagesOptions> = async (
+	model: ImagesModel<"openrouter-images">,
+	context: ImagesContext,
+	options?: ImagesOptions,
+) => {
+	try {
+		const module = await loadOpenRouterImagesProviderModule();
+		return await module.generateImages(model, context, options);
+	} catch (error) {
+		return createLazyLoadErrorImages(model, error);
+	}
+};
+
+export function registerBuiltInImagesApiProviders(): void {
+	registerImagesApiProvider({
+		api: "openrouter-images",
+		generateImages: generateImagesOpenRouter,
+	});
+}
+
+registerBuiltInImagesApiProviders();