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/unit/tw_branch_icon_uri.js

@@ -0,0 +1,46 @@
+const {test} = require('tap');
+const VirtualMachine = require('../../src/virtual-machine');
+const BlockType = require('../../src/extension-support/block-type');
+
+test('branchIconURI', t => {
+    const vm = new VirtualMachine();
+    vm.extensionManager._registerInternalExtension({
+        getInfo: () => ({
+            id: 'testextension',
+            name: 'test',
+            blocks: [
+                {
+                    blockType: BlockType.LOOP,
+                    opcode: 'block1',
+                    text: 'no custom icon'
+                },
+                {
+                    blockType: BlockType.LOOP,
+                    opcode: 'block2',
+                    text: 'LOOP with custom icon',
+                    branchIconURI: 'data:whatever1'
+                },
+                {
+                    blockType: BlockType.CONDITIONAL,
+                    opcode: 'block3',
+                    text: 'CONDITIONAL with custom icon',
+                    branchIconURI: 'data:whatever2'
+                },
+                {
+                    blockType: BlockType.LOOP,
+                    opcode: 'block4',
+                    text: 'LOOP with no icon',
+                    branchIconURI: ''
+                }
+            ]
+        })
+    });
+
+    const blocks = vm.runtime.getBlocksJSON();
+    t.equal(blocks[0].args2[0].src, 'media://repeat.svg', 'default custom icon');
+    t.equal(blocks[1].args2[0].src, 'data:whatever1', 'LOOP with custom icon');
+    t.equal(blocks[2].args2[0].src, 'data:whatever2', 'CONDITIONAL with custom icon');
+    t.same(blocks[3].args2, null, 'LOOP with no icon');
+
+    t.end();
+});