Zip Exports: Added attachment/image link resolving & JSON null handling

app/References/ModelResolvers/ImageModelResolver.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace BookStack\References\ModelResolvers;
+
+use BookStack\Uploads\Image;
+
+class ImageModelResolver implements CrossLinkModelResolver
+{
+    public function resolve(string $link): ?Image
+    {
+        $pattern = '/^' . preg_quote(url('/uploads/images'), '/') . '\/(.+)/';
+        $matches = [];
+        $match = preg_match($pattern, $link, $matches);
+        if (!$match) {
+            return null;
+        }
+
+        $path = $matches[1];
+
+        // Strip thumbnail element from path if existing
+        $originalPathSplit = array_filter(explode('/', $path), function (string $part) {
+            $resizedDir = (str_starts_with($part, 'thumbs-') || str_starts_with($part, 'scaled-'));
+            $missingExtension = !str_contains($part, '.');
+
+            return !($resizedDir && $missingExtension);
+        });
+
+        // Build a database-format image path and search for the image entry
+        $fullPath = '/uploads/images/' . ltrim(implode('/', $originalPathSplit), '/');
+
+        return Image::query()->where('path', '=', $fullPath)->first();
+    }
+}