feat: add Vue widget demo node and development support

- Add LoraManagerDemoNode to node mappings for Vue widget demonstration
- Update .gitignore to exclude Vue widget development artifacts (node_modules, .vite, dist)
- Implement automatic Vue widget build check in development mode with fallback handling
- Maintain pytest compatibility with proper import error handling

web/comfyui/vue-widgets/assets/demo-widget-RA_dFMfB.css

@@ -0,0 +1,56 @@
+
+.demo-widget-container[data-v-df0cb94d] {
+  padding: 12px;
+  box-sizing: border-box;
+  background: var(--comfy-menu-bg);
+  border-radius: 4px;
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+}
+.demo-title[data-v-df0cb94d] {
+  margin: 0 0 12px 0;
+  font-size: 16px;
+  font-weight: 600;
+  color: var(--fg-color);
+}
+.demo-content[data-v-df0cb94d] {
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
+  flex: 1;
+}
+.input-group[data-v-df0cb94d] {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}
+.input-group label[data-v-df0cb94d] {
+  font-size: 13px;
+  font-weight: 500;
+  color: var(--fg-color);
+}
+.demo-input[data-v-df0cb94d] {
+  width: 100%;
+}
+.button-group[data-v-df0cb94d] {
+  display: flex;
+  gap: 8px;
+  margin-top: 8px;
+}
+.result-card[data-v-df0cb94d] {
+  margin-top: 8px;
+  background: var(--comfy-input-bg);
+}
+.result-card[data-v-df0cb94d] .p-card-title {
+  font-size: 14px;
+  margin-bottom: 8px;
+}
+.result-card[data-v-df0cb94d] .p-card-content {
+  padding-top: 0;
+}
+.result-card p[data-v-df0cb94d] {
+  margin: 4px 0;
+  font-size: 13px;
+  color: var(--fg-color);
+}