fix(segmentation): restrict overlay segmentation menu to same frame of reference as viewport background display set (#5900)

- Add FrameOfReferenceUID to SEG and RTSTRUCT displaySet in SOP Class Handlers so the FOR is available for filtering
- Sync optimisticOverlayDisplaySets when background display set changes so the overlay menu reflects the correct state after a background switch
- Add FOR matching guard to the hydrate segmentation synchronizer to prevent the hydration synchronizer from blindly mirroring segmentations from a source viewport to a target viewport if their primary Frames of Reference do not align.
- fix segmentation overlay order reversal on viewport re-render

tests/pages/DataOverlayPageObject.ts

@@ -9,13 +9,16 @@ export class DataOverlayPageObject {
     this.viewportId = viewportId;
   }
 
+  get menu() {
+    return this.page.getByTestId(`viewport-data-overlay-menu-${this.viewportId}`);
+  }
+
   async toggle() {
     await this.page.getByTestId(`dataOverlayMenu-${this.viewportId}-btn`).click();
   }
 
   async addSegmentation(segmentation: string) {
-    await this.page.getByTestId(`AddSegmentationDataOverlay-${this.viewportId}`).click();
-    await this.page.getByText('SELECT A SEGMENTATION').click();
+    await this.openAddSegmentationDropdown();
     await this.page.getByTestId(segmentation).click();
   }
 
@@ -28,4 +31,32 @@ export class DataOverlayPageObject {
     await this.page.getByTestId(`overlay-ds-more-button-${segmentation}`).click();
     await this.page.getByTestId(`overlay-ds-remove-button-${segmentation}`).click();
   }
+
+  async openAddSegmentationDropdown() {
+    await this.page.getByTestId(`AddSegmentationDataOverlay-${this.viewportId}`).click();
+    await this.clickSelectSegmentation();
+  }
+
+  async clickSelectSegmentation() {
+    await this.page.getByText('SELECT A SEGMENTATION').click();
+  }
+
+  async getDropdownOptionLabels(): Promise<string[]> {
+    const options = this.page.getByRole('option');
+    const labels = (await options.allTextContents()).map(text => text.trim()).filter(Boolean);
+    return labels;
+  }
+
+  getOverlaySegmentationRow(label: string) {
+    return this.menu.getByTestId(`overlay-ds-select-value-${label.toUpperCase()}`);
+  }
+
+  get overlaySegmentationRows() {
+    return this.menu.locator('[data-cy^="overlay-ds-select-value-"]');
+  }
+
+  async changeBackgroundDisplaySet(backgroundLabel: string) {
+    await this.page.getByTestId(`overlay-background-ds-select-${this.viewportId}`).click();
+    await this.page.getByTestId(backgroundLabel).click();
+  }
 }