feat: support multiple image uploads for AI event generation 🖼️

- Updated OpenRouter integration to accept an array of image URLs
- Updated ImagePicker to use the `multiple` attribute natively
- Added `appendImagesDeduped` for handling client-side image deduplication
- Enhanced clipboard pasting to extract multiple images at once
- Rendered multiple images in a horizontal thumbnail strip in the AIToolbar
- Added tests to cover multi-image logic and AI request mapping

src/lib/types.ts

@@ -3,30 +3,35 @@ import { MAX_IMAGE_SIZE_BYTES } from "@/lib/constants";
 import { normalizeAiDateString } from "@/lib/date-normalizer";
 
 /** Validates that a base64 data URL string decodes to binary under the max size. */
-const isValidImageSize = (val: string | undefined): boolean => {
-	if (!val) return true;
+const isValidImageSize = (val: string): boolean => {
 	const base64Part = val.split(",")[1] ?? "";
 	const binarySize = Math.ceil(base64Part.length * 0.75);
 	return binarySize <= MAX_IMAGE_SIZE_BYTES;
 };
 
+/** Single image data-URL validator (reused inside the array schema). */
+const imageDataUrl = z
+	.string()
+	.regex(
+		/^data:image\/(png|jpeg|webp);base64,/,
+		"Must be a valid image data URL (PNG, JPEG, or WebP)",
+	)
+	.refine(isValidImageSize, {
+		message: "Image must be less than 10MB",
+	});
+
 export const AiEventRequestSchema = z
 	.object({
 		prompt: z.string().trim().max(2000).optional(),
-		imageBase64: z
-			.string()
-			.regex(
-				/^data:image\/(png|jpeg|webp);base64,/,
-				"Must be a valid image data URL (PNG, JPEG, or WebP)",
-			)
-			.refine(isValidImageSize, {
-				message: "Image must be less than 10MB",
-			})
-			.optional(),
+		/** Array of base64-encoded image data URLs (PNG, JPEG, WebP). */
+		images: z.array(imageDataUrl).optional(),
 	})
-	.refine((data) => data.prompt || data.imageBase64, {
-		message: "Either a prompt or an image is required",
-	});
+	.refine(
+		(data) =>
+			(data.prompt && data.prompt.trim().length > 0) ||
+			(data.images && data.images.length > 0),
+		{ message: "Either a prompt or at least one image is required" },
+	);
 
 export type AiEventRequest = z.infer<typeof AiEventRequestSchema>;