feat: BLENDER_CINEMATIC workflow graph node (M1)

Add StepName.BLENDER_CINEMATIC and full graph runtime support so cinematic
output types can be promoted from legacy_only to graph/shadow rollout mode.

- process_steps.py: add BLENDER_CINEMATIC = "blender_cinematic" enum value
- workflow_executor.py: map to render_cinematic_task in STEP_TASK_MAP
- workflow_node_registry.py: node definition with render/scene/camera fields
  (no animation params — cinematic is fixed at 250 frames @ 25fps)
- workflow_graph_runtime.py: _ORDER_LINE_RENDER_STEPS, _CINEMATIC_TASK_KEYS,
  shadow queue routing, predict_render_output_artifact (mp4),
  _build_task_kwargs, _artifact_kind_override_for_step
- tasks.py: _normalize_cinematic_params + render_cinematic_task Celery task
  (calls render_cinematic_to_file, publishes as turntable asset type since mp4)

No DB migration needed: admins can now manually set cinematic output types
to graph rollout mode via the admin panel and assign a workflow definition.

docs: learnings erfasst — BLENDER_CINEMATIC workflow graph node M1

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

backend/app/domains/rendering/workflow_graph_runtime.py

@@ -61,6 +61,7 @@ class WorkflowGraphState:
 _ORDER_LINE_RENDER_STEPS = {
     StepName.BLENDER_STILL,
     StepName.BLENDER_TURNTABLE,
+    StepName.BLENDER_CINEMATIC,
     StepName.EXPORT_BLEND,
     StepName.OUTPUT_SAVE,
     StepName.NOTIFY,
@@ -133,6 +134,33 @@ _TURNTABLE_TASK_KEYS = {
     "duration_s",
 }
 
+_CINEMATIC_TASK_KEYS = {
+    "width",
+    "height",
+    "engine",
+    "render_engine",
+    "samples",
+    "smooth_angle",
+    "cycles_device",
+    "transparent_bg",
+    "part_colors",
+    "template_path",
+    "target_collection",
+    "material_library_path",
+    "material_map",
+    "part_names_ordered",
+    "lighting_only",
+    "shadow_catcher",
+    "rotation_x",
+    "rotation_y",
+    "rotation_z",
+    "usd_path",
+    "focal_length_mm",
+    "sensor_width_mm",
+    "material_override",
+    "template_inputs",
+}
+
 _THUMBNAIL_TASK_KEYS = {
     "renderer",
     "render_engine",
@@ -232,6 +260,7 @@ def _resolve_shadow_render_queue(
     if node.step not in {
         StepName.BLENDER_STILL,
         StepName.BLENDER_TURNTABLE,
+        StepName.BLENDER_CINEMATIC,
         StepName.EXPORT_BLEND,
     }:
         return None
@@ -810,6 +839,27 @@ def _predict_task_output_metadata(
             "graph_notify_node_ids": list(task_kwargs.get("graph_notify_node_ids") or []),
         }
 
+    if node.step == StepName.BLENDER_CINEMATIC:
+        output_name_suffix = task_kwargs.get("output_name_suffix")
+        cinematic_filename = f"line_{order_line_id}_cinematic.mp4"
+        if output_name_suffix:
+            cinematic_filename = f"line_{order_line_id}_cinematic_{output_name_suffix}.mp4"
+        predicted_output_path = str(
+            build_order_line_step_render_path(step_path, order_line_id, cinematic_filename)
+        )
+        return {
+            "artifact_role": "cinematic_output",
+            "predicted_output_path": predicted_output_path,
+            "predicted_asset_type": "turntable",
+            "publish_asset_enabled": bool(task_kwargs.get("publish_asset_enabled", True)),
+            "graph_authoritative_output_enabled": bool(
+                task_kwargs.get("graph_authoritative_output_enabled", False)
+            ),
+            "graph_output_node_ids": list(task_kwargs.get("graph_output_node_ids") or []),
+            "notify_handoff_enabled": bool(task_kwargs.get("emit_legacy_notifications", False)),
+            "graph_notify_node_ids": list(task_kwargs.get("graph_notify_node_ids") or []),
+        }
+
     return {}
 
 
@@ -963,6 +1013,16 @@ def _build_task_kwargs(
                     "turntable.mp4",
                 ).parent
             )
+    elif node.step == StepName.BLENDER_CINEMATIC:
+        task_kwargs = _filter_graph_render_overrides(StepName.BLENDER_CINEMATIC, task_kwargs)
+        task_kwargs = {
+            key: value
+            for key, value in {
+                **render_defaults,
+                **task_kwargs,
+            }.items()
+            if key in _CINEMATIC_TASK_KEYS
+        }
     elif node.step == StepName.THUMBNAIL_SAVE:
         thumbnail_request = _resolve_thumbnail_request(workflow_context, state, node.id) or {}
         task_kwargs = {
@@ -980,6 +1040,7 @@ def _build_task_kwargs(
         StepName.BLENDER_STILL,
         StepName.EXPORT_BLEND,
         StepName.BLENDER_TURNTABLE,
+        StepName.BLENDER_CINEMATIC,
     }:
         connected_output_node_ids = _connected_node_ids_by_step(
             workflow_context,
@@ -1015,6 +1076,8 @@ def _build_task_kwargs(
 def _artifact_kind_override_for_step(step: StepName) -> str | None:
     if step == StepName.BLENDER_TURNTABLE:
         return "turntable_video"
+    if step == StepName.BLENDER_CINEMATIC:
+        return "cinematic_video"
     if step == StepName.BLENDER_STILL:
         return "still_image"
     if step == StepName.EXPORT_BLEND: