chore: snapshot workflow migration progress

.env.example

@@ -8,6 +8,18 @@ POSTGRES_PORT=5432
 # Redis
 REDIS_URL=redis://redis:6379/0
 
+# Prevent Python services from writing __pycache__ into bind-mounted source dirs.
+PYTHONDONTWRITEBYTECODE=1
+# Redirect any unavoidable bytecode writes away from bind mounts.
+PYTHONPYCACHEPREFIX=/tmp/pycache
+# Run Celery containers as your host user to avoid root-owned files on bind mounts.
+# Typical Linux value: `id -u`
+APP_UID=1000
+
+# Docker defaults:
+# - inside Compose, service discovery uses `postgres` / `redis`
+# - host-side tools and tests are normalized to `localhost` automatically by backend/app/config.py
+
 # JWT
 JWT_SECRET_KEY=your-secret-key-here-change-in-production
 JWT_ALGORITHM=HS256
@@ -39,5 +51,7 @@ MINIO_BUCKET=uploads
 # Blender >= 5.0.1 must be installed on the host at /opt/blender
 # The render-worker container mounts it read-only via volumes: - /opt/blender:/opt/blender:ro
 BLENDER_VERSION=5.0.1
+# Set explicitly to `cpu` on hosts without a usable NVIDIA/Cycles device to suppress startup warnings.
+CYCLES_DEVICE=gpu
 # Set to host path if Blender is not at /opt/blender:
 # BLENDER_BIN=/usr/local/blender/blender