Add storybook stories for Anchor behavior editors

Add stories for both the compact and full versions of the Anchor
behavior editor, along with Anchor behavior test data in TestProject.

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

Author: LuniMoon

newIDE/app/src/fixtures/TestProject.js

@@ -351,6 +351,11 @@ export const makeTestProject = (gd /*: libGDevelop */) /*: TestProject */ => {
     'DraggableBehavior::Draggable',
     'Draggable'
   );
+  spriteObjectWithBehaviors.addNewBehavior(
+    project,
+    'AnchorBehavior::AnchorBehavior',
+    'Anchor'
+  );
 
   const group1 = new gd.ObjectGroup();
   group1.setName('GroupOfSprites');

newIDE/app/src/stories/componentStories/ObjectEditor/AnchorBehaviorEditor.stories.js

@@ -0,0 +1,38 @@
+// @flow
+
+import * as React from 'react';
+import { action } from '@storybook/addon-actions';
+
+// Keep first as it creates the `global.gd` object:
+import { testProject } from '../../GDevelopJsInitializerDecorator';
+
+import paperDecorator from '../../PaperDecorator';
+import AnchorBehaviorEditor from '../../../BehaviorsEditor/Editors/AnchorBehaviorEditor';
+import SerializedObjectDisplay from '../../SerializedObjectDisplay';
+import fakeResourceManagementProps from '../../FakeResourceManagement';
+
+export default {
+  title: 'ObjectEditor/AnchorBehaviorEditor',
+  component: AnchorBehaviorEditor,
+  decorators: [paperDecorator],
+};
+
+export const Default = (): React.Node => {
+  const spriteObjectWithBehaviors = testProject.spriteObjectWithBehaviors;
+  const anchorBehavior = spriteObjectWithBehaviors.getBehavior('Anchor');
+
+  return (
+    <SerializedObjectDisplay object={spriteObjectWithBehaviors}>
+      <AnchorBehaviorEditor
+        project={testProject.project}
+        behavior={anchorBehavior}
+        object={spriteObjectWithBehaviors}
+        onBehaviorUpdated={action('onBehaviorUpdated')}
+        resourceManagementProps={fakeResourceManagementProps}
+        projectScopedContainersAccessor={
+          testProject.testSceneProjectScopedContainersAccessor
+        }
+      />
+    </SerializedObjectDisplay>
+  );
+};

newIDE/app/src/stories/componentStories/ObjectEditor/CompactAnchorBehaviorEditor.stories.js

@@ -0,0 +1,45 @@
+// @flow
+
+import * as React from 'react';
+import { action } from '@storybook/addon-actions';
+
+// Keep first as it creates the `global.gd` object:
+import { testProject } from '../../GDevelopJsInitializerDecorator';
+
+import paperDecorator from '../../PaperDecorator';
+import CompactAnchorBehaviorEditor from '../../../ObjectEditor/CompactObjectPropertiesEditor/CompactAnchorBehaviorEditor';
+import SerializedObjectDisplay from '../../SerializedObjectDisplay';
+import fakeResourceManagementProps from '../../FakeResourceManagement';
+
+const gd: libGDevelop = global.gd;
+
+export default {
+  title: 'ObjectEditor/CompactAnchorBehaviorEditor',
+  component: CompactAnchorBehaviorEditor,
+  decorators: [paperDecorator],
+};
+
+export const Default = (): React.Node => {
+  const spriteObjectWithBehaviors = testProject.spriteObjectWithBehaviors;
+  const anchorBehavior = spriteObjectWithBehaviors.getBehavior('Anchor');
+  const behaviorMetadata = gd.MetadataProvider.getBehaviorMetadata(
+    gd.JsPlatform.get(),
+    'AnchorBehavior::AnchorBehavior'
+  );
+
+  return (
+    <SerializedObjectDisplay object={spriteObjectWithBehaviors}>
+      <CompactAnchorBehaviorEditor
+        project={testProject.project}
+        behavior={anchorBehavior}
+        object={spriteObjectWithBehaviors}
+        behaviorMetadata={behaviorMetadata}
+        behaviorOverriding={null}
+        initialInstance={null}
+        onOpenFullEditor={action('onOpenFullEditor')}
+        onBehaviorUpdated={action('onBehaviorUpdated')}
+        resourceManagementProps={fakeResourceManagementProps}
+      />
+    </SerializedObjectDisplay>
+  );
+};