[eric] imports: extract schema getDefault into shared

frontend/src/shared/inputSchemaDefaults.ts

@@ -0,0 +1,29 @@
+export interface SchemaNode {
+  type?: string;
+  properties?: Record<string, SchemaNode>;
+  items?: SchemaNode;
+  required?: string[];
+  enum?: string[];
+  description?: string;
+  default?: any;
+}
+
+export function getDefault(schema: SchemaNode): any {
+  if (schema.default !== undefined) return schema.default;
+  switch (schema.type) {
+    case 'string': return '';
+    case 'number': return 0;
+    case 'boolean': return false;
+    case 'array': return [];
+    case 'object': {
+      const obj: Record<string, any> = {};
+      if (schema.properties) {
+        for (const [k, v] of Object.entries(schema.properties)) {
+          obj[k] = getDefault(v);
+        }
+      }
+      return obj;
+    }
+    default: return '';
+  }
+}