feat: consolidate testdrive-jsui to capabilities and implement plugin self-declaration

## Major Changes
- Moved all testdrive-jsui assets from root to capabilities/testdrive-jsui/
- Consolidated directory structure: js/, static/css/, static/images/, static/templates/
- Implemented plugin self-declaration (get_plugin_source_dir, get_asset_paths)
- Removed hardcoded plugin discovery from rendering.py
- Updated all asset paths to be relative to capability root

## Architecture Improvements
- Single source of truth for all testdrive-jsui assets
- Plugin declares its own location (no hardcoded paths)
- Generic plugin discovery using hasattr check
- Clean separation: all JS in .js files, no code mixing
- Standalone capability ready for independent use

## Files Changed
- markitect/plugins/testdrive_jsui.py: Added self-declaration methods
- markitect/plugins/rendering.py: Removed hardcoded discovery
- capabilities/testdrive-jsui/README.md: Added standalone usage documentation
- Moved 17 asset files to consolidated structure
- Deleted obsolete /testdrive-jsui/ root directory

## Testing
- All 17 assets verified and working
- Tested via CLI: markitect md-render --engine testdrive-jsui
- Full document rendering successful

Prepares testdrive-jsui to become a git submodule with proper dependency management.

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

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

capabilities/testdrive-jsui/static/css/controls.css

@@ -0,0 +1,129 @@
+/**
+ * TestDrive JSUI Control Panel Styles
+ *
+ * Styles for individual control panels
+ */
+
+/* Contents Control (Northwest) */
+.contents-control {
+    max-height: 300px;
+    overflow-y: auto;
+}
+
+.contents-control .toc-item {
+    padding: 0.25rem 0;
+    cursor: pointer;
+    border-radius: 3px;
+    padding-left: 0.5rem;
+}
+
+.contents-control .toc-item:hover {
+    background-color: #f8f9fa;
+}
+
+.contents-control .toc-h1 { font-weight: bold; }
+.contents-control .toc-h2 { margin-left: 1rem; }
+.contents-control .toc-h3 { margin-left: 2rem; font-size: 0.9em; }
+
+/* Status Control (East) */
+.status-control {
+    text-align: center;
+}
+
+.status-metric {
+    padding: 0.5rem;
+    margin: 0.25rem 0;
+    background: #f8f9fa;
+    border-radius: 4px;
+}
+
+.status-metric .metric-value {
+    font-size: 1.5em;
+    font-weight: bold;
+    color: #007bff;
+}
+
+.status-metric .metric-label {
+    font-size: 0.8em;
+    color: #6c757d;
+}
+
+/* Debug Control (Southeast) */
+.debug-control {
+    font-family: monospace;
+}
+
+/* Removed debug-header styles - using base class title formatting */
+
+.debug-control .debug-logs {
+    max-height: 200px;
+    overflow-y: auto;
+    background: #f8f9fa;
+    padding: 0.5rem;
+    margin: 0 -0.75rem -0.75rem -0.75rem;
+    border-radius: 0 0 5px 5px;
+    font-size: 0.8em;
+}
+
+/* Edit Control (Northeast) */
+.edit-control {
+    text-align: center;
+}
+
+.edit-control .control-button {
+    display: block;
+    width: 100%;
+    margin: 0.5rem 0;
+    padding: 0.5rem;
+    background: #007bff;
+    color: #fff;
+    border: none;
+    border-radius: 4px;
+    cursor: pointer;
+    font-size: 0.9em;
+}
+
+.edit-control .control-button:hover {
+    background: #0056b3;
+}
+
+.edit-control .control-button:disabled {
+    background: #6c757d;
+    cursor: not-allowed;
+}
+
+.edit-control .control-button.danger {
+    background: #dc3545;
+}
+
+.edit-control .control-button.danger:hover {
+    background: #c82333;
+}
+
+/* Control panel animations */
+.markitect-control-panel {
+    transition: all 0.3s ease;
+}
+
+.markitect-control-panel.entering {
+    opacity: 0;
+    transform: scale(0.9);
+}
+
+.markitect-control-panel.entered {
+    opacity: 1;
+    transform: scale(1);
+}
+
+/* Responsive adjustments */
+@media (max-width: 768px) {
+    .markitect-control-panel {
+        position: fixed !important;
+        top: auto !important;
+        bottom: 10px !important;
+        left: 10px !important;
+        right: 10px !important;
+        transform: none !important;
+        max-width: none !important;
+    }
+}