Adds proxy infrastructure for cross-process service access: BaseRegistry/
BaseProxy pattern, FolderPaths, ModelManagement, PromptServer, Progress,
Utils, HelperProxies, and WebDirectory proxies. These provide transparent
RPC access to host-side ComfyUI services from isolated child processes.
Adds the isolation system foundation: ComfyUIAdapter, extension loader,
manifest discovery, child/host process hooks, RPC bridge, runtime helpers,
SHM forensics, and the --use-process-isolation CLI flag.
pyisolate added to requirements.txt. .pyisolate_venvs/ added to .gitignore.
