Added batch process and test

templates/settings.html

@@ -113,6 +113,15 @@
              placeholder="0">
       <p class="muted small">Set to 0 to disable automatic sync. Changes take effect immediately on save. Examples: 60 = hourly, 1440 = daily.</p>
     </div>
+
+    <div class="form-row">
+      <label for="sync_batch_size">Batch size (zips per chunk)</label>
+      <input id="sync_batch_size" name="sync_batch_size" type="number"
+             min="0" step="1" style="width:8rem"
+             value="{{ s.get('sync_batch_size','0') }}"
+             placeholder="0">
+      <p class="muted small">Each sync run processes <strong>all</strong> unprocessed files, but works through them in chunks of this size to limit temp disk usage. Set to 0 to process all at once.</p>
+    </div>
   </section>
 
   <div class="form-actions">