Restructure things so that the application is now just another module.

Kohana makes this type of transition fairly straightforward in that
all controllers/helpers/etc are still located in the cascading
filesystem without any extra effort, except that I've temporarily
added a hack to force modules/gallery into the module path.

Rename what's left of "core" to be "application" so that it conforms
more closely to the Kohana standard (basically, just
application/config/config.php which is the minimal thing that you need
in the application directory)

There's still considerable work left to be done here.

modules/gallery/views/admin_maintenance_task.html.php

@@ -0,0 +1,32 @@
+<?php defined("SYSPATH") or die("No direct script access.") ?>
+<script type="text/javascript">
+  update = function() {
+    $.ajax({
+      url: "<?= url::site("admin/maintenance/run/$task->id?csrf=$csrf") ?>",
+      dataType: "json",
+      success: function(data) {
+        $(".gProgressBar").progressbar("value", data.task.percent_complete);
+        $("#gStatus").html("" + data.task.status);
+        if (data.task.done) {
+          $("#gPauseButton").hide();
+          $("#gDoneButton").show();
+        } else {
+          setTimeout(update, 100);
+        }
+      }
+    });
+  }
+  $(".gProgressBar").progressbar({value: 0});
+  update();
+  dismiss = function() {
+    window.location.reload();
+  }
+</script>
+<div id="gProgress">
+  <div class="gProgressBar"></div>
+  <div id="gStatus"></div>
+  <div>
+    <button id="gPauseButton" class="ui-state-default ui-corner-all" onclick="dismiss()"><?= t("Pause") ?></button>
+    <button id="gDoneButton" class="ui-state-default ui-corner-all" style="display: none" onclick="dismiss()"><?= t("Done") ?></button>
+  </div>
+</div>