feat(accounting): document colleague trades on configured accounts

Post Montzar-covered buy/sell to Zarin/Tahesab/Pargar using montzar_account_* settings, and harden public storage URL/MIME handling for uploads.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Http/Controllers/PublicStorageController.php

@@ -50,9 +50,37 @@ class PublicStorageController extends Controller
      */
     private function candidatePaths(string $path): array
     {
-        return [
-            storage_path('app/public/'.$path),
-            public_path('storage/'.$path),
-        ];
+        $relative = [$path, ...$this->alternateExtensionPaths($path)];
+        $full = [];
+        foreach ($relative as $rel) {
+            $full[] = storage_path('app/public/'.$rel);
+            $full[] = storage_path('app/public/storage/'.$rel);
+            $full[] = public_path('storage/'.$rel);
+        }
+
+        return $full;
+    }
+
+    /**
+     * آپلود ادمین WebP می‌سازد ولی const گاهی همان هش را با .png نگه می‌دارد.
+     *
+     * @return list<string>
+     */
+    private function alternateExtensionPaths(string $path): array
+    {
+        if (! preg_match('/^(.*)\.([a-z0-9]+)$/i', $path, $matches)) {
+            return [];
+        }
+
+        $stem = $matches[1];
+        $ext = strtolower($matches[2]);
+        $out = [];
+        foreach (['webp', 'png', 'jpg', 'jpeg', 'gif'] as $alt) {
+            if ($alt !== $ext) {
+                $out[] = $stem.'.'.$alt;
+            }
+        }
+
+        return $out;
     }
 }