refactor: reorganize src structure

src/core/shared.ts

@@ -0,0 +1,19 @@
+export type ScenePayload = {
+  elements: unknown[];
+  appState: Record<string, unknown>;
+  files: Record<string, unknown>;
+};
+
+export type DrawingMeta = {
+  id: string;
+  title: string;
+  createdAt: string;
+  updatedAt: string;
+  revision: number;
+};
+
+export type DrawingRecord = DrawingMeta & {
+  scene: ScenePayload;
+};
+
+export const DEFAULT_TITLE = "Untitled";