fix: add missing conditionalSwitch to quickstart validation defaults

Pre-existing type error — conditionalSwitch was missing from the
createDefaultNodeData switch in validation.ts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/lib/quickstart/validation.ts

@@ -387,6 +387,12 @@ function createDefaultNodeData(type: NodeType): WorkflowNodeData {
         status: "idle",
         error: null,
       };
+    case "router":
+      return {};
+    case "switch":
+      return { inputType: null, switches: [{ id: "sw-1", name: "Output 1", enabled: true }] };
+    case "conditionalSwitch":
+      return { incomingText: null, rules: [{ id: "rule-1", value: "", mode: "contains", label: "Rule 1", isMatched: false }] };
     case "glbViewer":
       return {
         glbUrl: null,