fix: Blender 5.0 Action.fcurves API change — safe LINEAR keyframe setting

Blender 5.0 renamed Action.fcurves. Now tries fcurves first, falls
back to channels, and wraps in try/except so the render proceeds
even if LINEAR interpolation can't be set.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

render-worker/scripts/cinematic_render.py

@@ -380,20 +380,30 @@ def _setup_cinematic_camera(parts, bbox_center, bsphere_radius, total_frames):
         cam_obj.data.dof.keyframe_insert(data_path="aperture_fstop", frame=frame)
 
     # Set all keyframes to LINEAR interpolation (no bezier smoothing)
-    if cam_obj.animation_data and cam_obj.animation_data.action:
-        for fcurve in cam_obj.animation_data.action.fcurves:
-            for kp in fcurve.keyframe_points:
-                kp.interpolation = 'LINEAR'
-    if cam_obj.data.animation_data and cam_obj.data.animation_data.action:
-        for fcurve in cam_obj.data.animation_data.action.fcurves:
-            for kp in fcurve.keyframe_points:
-                kp.interpolation = 'LINEAR'
-    if cam_obj.data.dof.animation_data and cam_obj.data.dof.animation_data.action:
-        for fcurve in cam_obj.data.dof.animation_data.action.fcurves:
-            for kp in fcurve.keyframe_points:
-                kp.interpolation = 'LINEAR'
+    def _set_linear(anim_data):
+        if not anim_data or not anim_data.action:
+            return
+        action = anim_data.action
+        # Blender 5.0+: action.fcurves may be action.channels or similar
+        curves = None
+        if hasattr(action, 'fcurves'):
+            curves = action.fcurves
+        elif hasattr(action, 'channels'):
+            curves = action.channels
+        if curves:
+            for fc in curves:
+                for kp in fc.keyframe_points:
+                    kp.interpolation = 'LINEAR'
 
-    print(f"[cinematic_render] camera keyframed: {total_frames} frames across {len(SEGMENTS)} segments (LINEAR interpolation)", flush=True)
+    try:
+        _set_linear(cam_obj.animation_data)
+        _set_linear(cam_obj.data.animation_data)
+        if hasattr(cam_obj.data, 'dof') and cam_obj.data.dof:
+            _set_linear(getattr(cam_obj.data.dof, 'animation_data', None))
+    except Exception as e:
+        print(f"[cinematic_render] WARNING: could not set LINEAR interpolation: {e}", flush=True)
+
+    print(f"[cinematic_render] camera keyframed: {total_frames} frames across {len(SEGMENTS)} segments", flush=True)
     return cam_obj