[lesnik512]

Closes #45

setup_di(app, container) takes a keyword-only manage_lifespan: bool = True, with the same name and default as modern-di-fastmcp. The default changes nothing.

With manage_lifespan=False the four worker signal handlers skip open() and close_sync(). Everything else still runs: the worker_process_init handler still binds the container to a spawn child's app, each handler still acts only for the app that owns the container, and @inject still builds, opens and closes a child container per task call. The user owns the root container, for example with async with container: around running the apps.

The check sits in two small helpers, _open_for and _close_for, so the binding call in the process-init handler runs before the flag is consulted.

README: the flag is in the API table, and a new "Sharing a container" section shows the user owning the root. It also says that a prefork child inherits the open container and nothing closes it there with the flag off, so the user closes it from their own worker_process_shutdown handler if the child's APP finalizers must run. CONTEXT.md: the root container entry notes that the flag hands opening and closing to the user.

Tests, each written to fail before the change:

• a full worker lifecycle (both signal pairs and one task) leaves the root open with its APP finalizer unrun, while the task's REQUEST-scoped dependency resolves and its finalizer runs
• the init signals do not reopen a closed root
• with the user owning the root in async with, the APP finalizer runs once, at the user's exit
• a spawn child still binds its container to the current app and leaves it closed

Existing tests for the default are unchanged.