Changed default user UID and GID to 1000, added file permissions checking on startup, add fix-permissions script

[akatz-ai]

• Force comfy user to 1000:1000 to match default WSL distro user permissions.
  • user uid and gid can be changed via the WANTED_UID and WANTED_GID environment variables
  • (e.g. WANTED_UID=1024,WANTED_GID=1024)
• Added permissions checking on initial container startup:
  • permission checking mode can be set via the PERMISSION_CHECK_MODE environment variable.
  • PERMISSION_CHECK_MODE=once is the default, will check container files for permissions only on initial startup.
  • PERMISSION_CHECK_MODE=startup will run the permissions checking script on every container startup.
  • PERMISSION_CHECK_MODE=never will never run the permissions checking script.
• Added a fix-permissions script which can be run via exec into the container (use comfydock dev exec for a convenient way to do so) and running the command fix-permissions.