feat: implement document actions for managing artboards, zoom, and history; update UI components to utilize new actions

app/document-actions.test.ts

@@ -0,0 +1,34 @@
+import { describe, expect, test } from "bun:test";
+import { commandIds } from "@commands/ids";
+import { createImageStudioApp } from "./app";
+
+describe("document actions", () => {
+  test("share zoom, fit, and history behavior across UI entry points", () => {
+    const app = createImageStudioApp();
+    const artboard = app.store.getState().document.artboards[0];
+    if (!artboard) throw new Error("Expected the default artboard.");
+
+    app.actions.document.zoomTo(2);
+    app.actions.document.zoomBy(0.5);
+    expect(app.store.getState().editor.viewport.zoom).toBe(1);
+
+    app.actions.document.fitArtboard(artboard.id);
+    expect(app.store.getState().editor.viewport.center).toEqual({ x: 0, y: 0 });
+
+    expect(app.actions.document.canUndo()).toBe(true);
+    app.actions.document.undo();
+    expect(app.store.getState().document.artboards).toHaveLength(0);
+    expect(app.actions.document.canRedo()).toBe(true);
+    app.actions.document.redo();
+    expect(app.store.getState().document.artboards).toHaveLength(1);
+  });
+
+  test("opens Generate through the canonical workspace command", () => {
+    const app = createImageStudioApp({ createDefaultArtboard: false });
+    app.actions.document.openGenerate();
+    expect(app.store.getState().editor.workspace.panel).toBe("generate");
+
+    app.store.dispatch(commandIds.workspaceSetPanel, { panel: "none" });
+    expect(app.store.getState().editor.workspace.panel).toBe("none");
+  });
+});