feat: add refactored testdrive-jsui capability with consolidated architecture

Complete integration of refactored testdrive-jsui capability:

## Refactored Architecture
- js/ - All JavaScript source (controls, components, core)
- static/ - CSS, images, templates
- src/testdrive_jsui/ - Python package
- tests/ - Python tests

## Plugin Self-Declaration
- get_plugin_source_dir() - plugin declares own location
- get_asset_paths() - organized asset paths
- No hardcoded discovery logic

## Merged Content
- Baseline UI scaffold (tutorials, LICENSE, INTRODUCTION.md)
- Refactored capability implementation
- Comprehensive documentation

Ready for standalone use or integration with markitect.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

js/tests/jest.setup.js

@@ -0,0 +1,26 @@
+/**
+ * Jest Setup File for JavaScript UI Tests
+ *
+ * Sets up environment and global utilities for testing.
+ * Jest with jsdom environment already provides DOM globals.
+ */
+
+// Add TextEncoder/TextDecoder polyfills for Node.js compatibility
+const { TextEncoder, TextDecoder } = require('util');
+global.TextEncoder = TextEncoder;
+global.TextDecoder = TextDecoder;
+
+// Mock console methods to reduce noise in tests
+const originalLog = console.log;
+console.log = (...args) => {
+    // Only log if DEBUG_TESTS environment variable is set
+    if (process.env.DEBUG_TESTS) {
+        originalLog(...args);
+    }
+};
+
+// Setup DOM fixtures after page load
+beforeEach(() => {
+    // Reset document body for each test
+    document.body.innerHTML = '<div id="content"></div>';
+});