Add downsample series functionality and related UI updates

- Implemented asynchronous downsample task for series with progress tracking.
- Added new URL endpoint for downsample status.
- Updated Series model to include source_series_instance_uid.
- Enhanced case display template with new buttons for series actions.
- Added password reset functionality in user profile with appropriate alerts.
- Created migration for new source_series_instance_uid field in Series model.

atlas/tasks.py

@@ -92,6 +92,106 @@ from django.core.cache import cache
 import copy
 import io
 
+
+@task(takes_context=True)
+def series_downsample_task(context, series_id, user_id, downsample_pct):
+    """Downsample a series asynchronously while preserving hash continuity."""
+    from loguru import logger
+    from atlas import views as atlas_views
+
+    progress_key = f"series_downsample_progress:{context.task_result.id}"
+    cache.set(
+        progress_key,
+        {"current": 0, "total": 0, "message": "Preparing downsample..."},
+        timeout=60 * 60,
+    )
+
+    series = get_object_or_404(Series, pk=series_id)
+    user = get_object_or_404(User, pk=user_id)
+
+    if not series.check_user_can_edit(user):
+        raise PermissionError("Permission denied")
+
+    images = list(series.get_images())
+    total_images = len(images)
+    replacement_series_uid = generate_uid()
+    source_series_uid = series.series_instance_uid
+    updated_images = []
+
+    cache.set(
+        progress_key,
+        {"current": 0, "total": total_images, "message": "Downsample started"},
+        timeout=60 * 60,
+    )
+
+    for idx, image in enumerate(images, start=1):
+        ds = atlas_views._read_series_image_dataset(image)
+        if ds is None:
+            cache.set(
+                progress_key,
+                {"current": idx, "total": total_images, "message": f"Skipping unreadable image ({idx}/{total_images})"},
+                timeout=60 * 60,
+            )
+            continue
+
+        try:
+            original_hash = image.image_blake3_hash
+            ds_out = atlas_views._downsample_dicom_dataset(
+                ds,
+                int(downsample_pct),
+                series_instance_uid=replacement_series_uid,
+                source_series_instance_uid=source_series_uid,
+                series_description=series.description,
+            )
+            out_io = io.BytesIO()
+            ds_out.save_as(out_io, write_like_original=False)
+            out_io.seek(0)
+
+            image.image.save(
+                f"downsample_{downsample_pct}_{image.pk}.dcm",
+                ContentFile(out_io.getvalue()),
+                save=False,
+            )
+            image.image_blake3_hash = original_hash
+            image.save(update_fields=["image", "image_blake3_hash"])
+            updated_images.append(image.pk)
+        except Exception as exc:
+            logger.warning("Downsample failed for image {}: {}", image.pk, exc)
+
+        cache.set(
+            progress_key,
+            {
+                "current": idx,
+                "total": total_images,
+                "message": f"Downsampling image {idx}/{total_images}",
+            },
+            timeout=60 * 60,
+        )
+
+    if updated_images:
+        series.modified = Series.SeriesModifiedChocies.RE
+        series.source_series_instance_uid = source_series_uid
+        series.series_instance_uid = replacement_series_uid
+        series.save(update_fields=["modified", "source_series_instance_uid", "series_instance_uid"])
+
+    cache.set(
+        progress_key,
+        {
+            "current": total_images,
+            "total": total_images,
+            "message": "Downsample complete",
+        },
+        timeout=10 * 60,
+    )
+
+    return {
+        "series_id": series.pk,
+        "downsample_pct": int(downsample_pct),
+        "updated_images": len(updated_images),
+        "series_instance_uid": replacement_series_uid,
+        "source_series_instance_uid": source_series_uid,
+    }
+
 @task
 def push_case_to_cimar_task(case_id):
     """Sends an email when the feedback form has been submitted."""
@@ -389,8 +489,6 @@ def series_reconstruct_task(
 
     for plane_norm, cfg in plane_builders.items():
         recon_series = atlas_views._create_series_derivative(series, f"Recon {plane_norm.title()} ({source_plane.title()} src)")
-        recon_series.series_instance_uid = generate_uid()
-        recon_series.save(update_fields=["series_instance_uid"])
 
         for idx in range(int(cfg["count"])):
             arr2d = cfg["slice_fn"](idx)
@@ -403,6 +501,7 @@ def series_reconstruct_task(
             atlas_views._stamp_derived_dataset(
                 ds_new,
                 series_instance_uid=recon_series.series_instance_uid,
+                source_series_instance_uid=series.series_instance_uid,
                 series_description=recon_series.description or f"Recon {plane_norm.title()}",
                 derivation_description=(
                 f"{plane_norm.title()} reconstruction; mode={recon_thickness_mode}; "