fix(dicom-pdf): enhance PDF loading with authentication support

- move authenticated rendered media loading into the datasource\n- route DICOM video display sets through Cornerstone video viewports\n- add a 3.12 to 3.13 migration note for the removed DICOM-video viewport namespace

platform/docs/docs/migration-guide/3p12-to-3p13/dicom-video.md

@@ -0,0 +1,74 @@
+---
+sidebar_position: 8
+sidebar_label: DICOM video viewport
+title: DICOM video viewport migration
+---
+
+# DICOM video viewport migration
+
+The `@ohif/extension-dicom-video` extension no longer provides its own viewport module in 3.13. DICOM video rendering is handled by the Cornerstone viewport, which supports Cornerstone3D video viewports directly.
+
+The DICOM video SOP class handler remains available and should still be used to identify and build video display sets:
+
+```ts
+'@ohif/extension-dicom-video.sopClassHandlerModule.dicom-video'
+```
+
+## What changed
+
+The following viewport namespace has been removed:
+
+```ts
+'@ohif/extension-dicom-video.viewportModule.dicom-video'
+```
+
+Use the Cornerstone viewport namespace instead:
+
+```ts
+'@ohif/extension-cornerstone.viewportModule.cornerstone'
+```
+
+## Migration
+
+If your mode has a dedicated DICOM video viewport entry, replace it with the Cornerstone viewport or add the video SOP class handler to an existing Cornerstone viewport entry.
+
+**Before (3.12):**
+
+```ts
+const dicomvideo = {
+  sopClassHandler: '@ohif/extension-dicom-video.sopClassHandlerModule.dicom-video',
+  viewport: '@ohif/extension-dicom-video.viewportModule.dicom-video',
+};
+
+viewports: [
+  {
+    namespace: '@ohif/extension-cornerstone.viewportModule.cornerstone',
+    displaySetsToDisplay: [ohif.sopClassHandler],
+  },
+  {
+    namespace: dicomvideo.viewport,
+    displaySetsToDisplay: [dicomvideo.sopClassHandler],
+  },
+];
+```
+
+**After (3.13):**
+
+```ts
+const dicomvideo = {
+  sopClassHandler: '@ohif/extension-dicom-video.sopClassHandlerModule.dicom-video',
+};
+
+viewports: [
+  {
+    namespace: '@ohif/extension-cornerstone.viewportModule.cornerstone',
+    displaySetsToDisplay: [ohif.sopClassHandler, dicomvideo.sopClassHandler],
+  },
+];
+```
+
+If your mode uses a custom viewport that wraps `OHIFCornerstoneViewport` (for example, a tracked Cornerstone viewport), route DICOM video display sets through that wrapper instead of the removed DICOM video viewport namespace.
+
+## Why
+
+Keeping video rendering in the Cornerstone viewport avoids a separate custom React video viewport path and keeps video behavior aligned with Cornerstone3D viewport services, tools, annotations, and presentation state handling.

platform/docs/docs/migration-guide/3p12-to-3p13/index.md

@@ -23,5 +23,8 @@ The largest changes in 3.13 are infrastructure-level:
   is now **24**.
 - **[SegmentationService](./segmentation-service.md)** — the
   `removeSegmentationRepresentations` method was renamed.
+- **[DICOM video viewport](./dicom-video.md)** — the
+  `@ohif/extension-dicom-video.viewportModule.dicom-video` namespace was
+  removed; route DICOM video display sets through the Cornerstone viewport.
 
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