fix(blender): use shutil.move for cross-fs copy, disable denoiser

os.rename fails across Docker volume boundaries (different filesystems).
Debian Blender 3.4 lacks OpenImageDenoiser — disable denoising in prompt.

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

docker/blender-worker/server.py

@@ -3,6 +3,7 @@
 import json
 import os
 import random
+import shutil
 import string
 import subprocess
 import time
@@ -78,7 +79,7 @@ class RenderHandler(BaseHTTPRequestHandler):
         dest = os.path.join(GENERATED_DIR, filename)
 
         os.makedirs(GENERATED_DIR, exist_ok=True)
-        os.rename(render_path, dest)
+        shutil.move(render_path, dest)
 
         self._json_response(200, {
             "success": True,

server/index.ts

@@ -1589,7 +1589,7 @@ The script should:
 - Clear the default scene (delete all default objects)
 - Create the described objects with materials and colors
 - Set up basic lighting (sun + area light) and camera positioned to frame the scene
-- Use Cycles render engine with CPU device: bpy.context.scene.render.engine = "CYCLES" and bpy.context.scene.cycles.device = "CPU" and bpy.context.scene.cycles.samples = 64
+- Use Cycles render engine with CPU device: bpy.context.scene.render.engine = "CYCLES" and bpy.context.scene.cycles.device = "CPU" and bpy.context.scene.cycles.samples = 64 and bpy.context.scene.cycles.use_denoising = False
 - Render to /tmp/render.png at 1024x1024 with bpy.context.scene.render.image_settings.file_format = "PNG"
 
 Output ONLY the Python code, no explanations or comments outside the code.`);