Add update-vendor.sh symlink support, unify install.sh vendor flow

- update-vendor.sh now creates webui/vendor symlinks (htm.js)
- install.sh calls update-vendor.sh after package install
- Add vendor/.empty and webui/vendor/.empty as directory placeholders in git

webui/static/style.css

@@ -699,6 +699,82 @@ body {
     text-align: center;
 }
 
+/* ApplyConfirm modal */
+.apply-subsystem-row {
+    display: flex;
+    align-items: center;
+    padding: 8px 0;
+    border-bottom: 1px solid var(--border);
+    cursor: default;
+}
+
+.apply-subsystem-row.pending {
+    cursor: pointer;
+}
+
+.apply-subsystem-row.pending:hover {
+    background: rgba(0, 180, 216, 0.08);
+}
+
+.apply-subsystem-name {
+    flex: 1;
+    font-weight: 600;
+    font-size: 14px;
+}
+
+.apply-subsystem-status {
+    margin-left: 12px;
+    color: var(--text-muted);
+    font-size: 13px;
+}
+
+.apply-subsystem-status.pending {
+    color: var(--warning);
+    font-weight: 500;
+}
+
+.apply-expand-icon {
+    margin-left: 8px;
+    transition: transform 0.2s;
+    font-size: 12px;
+}
+
+.apply-expand-icon.expanded {
+    transform: rotate(90deg);
+}
+
+.apply-detail-section {
+    padding: 8px 12px;
+    background: rgba(0, 0, 0, 0.15);
+    margin: 4px 0 4px 12px;
+    border-radius: 4px;
+    font-size: 13px;
+}
+
+.apply-detail-item {
+    padding: 4px 0;
+    border-bottom: 1px solid var(--border);
+}
+
+.apply-detail-item:last-child {
+    border-bottom: none;
+}
+
+.apply-modal-actions {
+    display: flex;
+    justify-content: flex-end;
+    gap: 8px;
+    padding-top: 12px;
+    margin-top: 12px;
+    border-top: 1px solid var(--border);
+}
+
+.apply-no-changes {
+    padding: 16px;
+    text-align: center;
+    color: var(--text-muted);
+}
+
 /* Responsive */
 @media (max-width: 768px) {
     .sidebar {