fix: cinematic output type guard + legacy_only migration

- Migration 070: seeds 'Cinematic Highlight' output type (legacy_only, no
  workflow link) for fresh installs
- Migration 071: patches existing cinematic output types — clears
  workflow_definition_id and forces legacy_only rollout mode. The row
  existed since 2026-03 with shadow mode + a linked workflow def;
  no BLENDER_CINEMATIC graph node exists so shadow execution would fail.
- API guard in output_types POST + PATCH: cinematic output types cannot
  receive a workflow_definition_id (HTTP 400)
- Defense-in-depth in dispatch_service: early legacy exit if
  render_settings.cinematic is true, regardless of rollout mode
- docs: learning erfasst — cinematic rollout mode footgun

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

backend/alembic/versions/070_seed_cinematic_output_type.py

@@ -0,0 +1,59 @@
+"""Seed 'Cinematic Highlight' output type.
+
+Revision ID: 070
+Revises: 069
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "070"
+down_revision = "069"
+branch_labels = None
+depends_on = None
+
+_NAME = "Cinematic Highlight"
+
+
+def upgrade() -> None:
+    op.execute(
+        sa.text(
+            f"""
+            INSERT INTO output_types (
+                id, name, description, renderer, render_settings,
+                output_format, sort_order, compatible_categories, render_backend,
+                is_animation, transparent_bg, workflow_family, artifact_kind,
+                invocation_overrides, cycles_device, pricing_tier_id, is_active,
+                tenant_id, material_override, workflow_definition_id,
+                workflow_rollout_mode, created_at, updated_at
+            ) VALUES (
+                gen_random_uuid(),
+                '{_NAME}',
+                'Cinematic highlight animation: 4-segment camera orbit, depth-of-field, '
+                '250 frames @ 25 fps (10 s), 1920x1080 MP4. '
+                'Runs legacy-only — no workflow graph node exists for cinematic.',
+                'blender',
+                '{{"cinematic": true, "samples": 128, "width": 1920, "height": 1080}}'::jsonb,
+                'mp4',
+                50,
+                '[]'::jsonb,
+                'celery',
+                true,
+                false,
+                'order_line',
+                'turntable_video',
+                '{{}}'::jsonb,
+                NULL, NULL, true, NULL, NULL, NULL,
+                'legacy_only',
+                now(), now()
+            )
+            ON CONFLICT (name) DO NOTHING
+            """
+        )
+    )
+
+
+def downgrade() -> None:
+    op.execute(
+        sa.text("DELETE FROM output_types WHERE name = :name").bindparams(name=_NAME)
+    )

backend/alembic/versions/071_fix_cinematic_output_type_rollout.py

@@ -0,0 +1,35 @@
+"""Fix cinematic output types: force legacy_only rollout, clear workflow link.
+
+No BLENDER_CINEMATIC node exists in the workflow graph system. Any cinematic
+output type with a workflow_definition_id set would cause the shadow/graph
+execution path to attempt a graph run and fail silently.
+
+Revision ID: 071
+Revises: 070
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "071"
+down_revision = "070"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.execute(
+        sa.text(
+            """
+            UPDATE output_types
+            SET
+                workflow_rollout_mode = 'legacy_only',
+                workflow_definition_id = NULL
+            WHERE (render_settings->>'cinematic')::boolean IS TRUE
+            """
+        )
+    )
+
+
+def downgrade() -> None:
+    pass

backend/app/api/routers/output_types.py

@@ -271,6 +271,13 @@ async def create_output_type(
     if body.workflow_definition_id is None:
         data["workflow_rollout_mode"] = "legacy_only"
 
+    if data.get("render_settings", {}).get("cinematic") and body.workflow_definition_id is not None:
+        raise HTTPException(
+            400,
+            detail="Cinematic output types cannot be linked to a workflow definition. "
+                   "No BLENDER_CINEMATIC node exists in the workflow graph; cinematic renders use the legacy path only.",
+        )
+
     ot = OutputType(**data)
     db.add(ot)
     await db.commit()
@@ -387,6 +394,14 @@ async def update_output_type(
     if candidate_workflow_definition_id is None:
         data["workflow_rollout_mode"] = "legacy_only"
 
+    candidate_render_settings = data.get("render_settings", ot.render_settings) or {}
+    if candidate_render_settings.get("cinematic") and candidate_workflow_definition_id is not None:
+        raise HTTPException(
+            400,
+            detail="Cinematic output types cannot be linked to a workflow definition. "
+                   "No BLENDER_CINEMATIC node exists in the workflow graph; cinematic renders use the legacy path only.",
+        )
+
     for field_name, value in data.items():
         setattr(ot, field_name, value)
     await db.commit()

backend/app/domains/rendering/dispatch_service.py

@@ -193,6 +193,30 @@ def dispatch_render_with_workflow(order_line_id: str) -> dict:
             )
             return legacy_result
 
+        # Cinematic output types have no BLENDER_CINEMATIC graph node — force legacy regardless
+        # of what workflow_rollout_mode or workflow_definition_id say.
+        if output_type and isinstance(output_type.render_settings, dict) and output_type.render_settings.get("cinematic"):
+            logger.warning(
+                "order_line %s: output_type %s is cinematic but has a workflow_definition_id set; "
+                "forcing legacy dispatch (no BLENDER_CINEMATIC node exists in the workflow graph)",
+                order_line_id,
+                output_type.id,
+            )
+            legacy_result = _legacy_dispatch(order_line_id)
+            legacy_result.update(
+                _build_rollout_signal(
+                    gate_status="cinematic_legacy_only",
+                    ready=False,
+                    reasons=[
+                        "Cinematic output types always use the legacy dispatch path.",
+                        "Remove the workflow_definition_id link to silence this warning.",
+                    ],
+                    workflow_def_id=wf_def.id,
+                    output_type_id=output_type.id,
+                )
+            )
+            return legacy_result
+
         configured_execution_mode = get_workflow_execution_mode(canonical_config, default="legacy")
         workflow_rollout_mode = _normalize_workflow_rollout_mode(
             getattr(output_type, "workflow_rollout_mode", None)