feat: add image_id to button parameters for OBZ image loading

Store image_id in button.parameters to enable web viewers to fetch
images via API endpoint instead of embedding large data URLs.

Author: willwade

src/processors/obfProcessor.ts

@@ -232,10 +232,14 @@ class ObfProcessor extends BaseProcessor {
       }
 
       // Build parameters object for Grid3 export compatibility
-      const buttonParameters: { imageData?: Buffer; [key: string]: any } = {};
+      const buttonParameters: { imageData?: Buffer; image_id?: string; [key: string]: any } = {};
       if (imageBuffer) {
         buttonParameters.imageData = imageBuffer;
       }
+      // Store image_id for web viewers to fetch images via API
+      if (btn.image_id) {
+        buttonParameters.image_id = btn.image_id;
+      }
 
       return new AACButton({
         // Make button ID unique by combining page ID and button ID