Initial commit of 001code-html Scratch frontend project.

Includes scratch-gui, scratch-vm, scratch-blocks, scratch-render, scratch-l10n, and deployment config.

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

scratch-vm/test/integration/tw_serialize_hidden_monitors.js

@@ -0,0 +1,31 @@
+const Runtime = require('../../src/engine/runtime');
+const {test} = require('tap');
+const {serialize} = require('../../src/serialization/sb3');
+const MonitorRecord = require('../../src/engine/monitor-record');
+
+test('does not serialize hidden monitors from extensions', t => {
+    const rt = new Runtime();
+    rt.requestAddMonitor(MonitorRecord({
+        id: 'timer',
+        opcode: 'sensing_timer',
+        visible: true
+    }));
+    rt.requestAddMonitor(MonitorRecord({
+        id: 'other_monitor',
+        opcode: 'tw_someOpcodeThatIsntPartOfACoreExtension',
+        visible: true
+    }));
+
+    const monitorsWhenVisible = serialize(rt).monitors;
+    t.ok(monitorsWhenVisible[0].id === 'timer');
+    t.ok(monitorsWhenVisible[1].id === 'other_monitor');
+    t.equal(monitorsWhenVisible.length, 2);
+
+    rt.requestHideMonitor('timer');
+    rt.requestHideMonitor('other_monitor');
+    const monitorsWhenHidden = serialize(rt).monitors;
+    t.ok(monitorsWhenHidden[0].id === 'timer');
+    t.equal(monitorsWhenHidden.length, 1);
+
+    t.end();
+});