feat: ✨ Add threadsafe parameter to instance getters

[remimd]

No description provided.

[Copilot]

Pull Request Overview

This PR adds a threadsafe flag to all instance‐retrieval methods, introduces a shared get_lock helper for locking, updates FastAPI integration to expose a InjectThreadSafe alias, and adjusts tests to expect NotImplemented as the missing‐instance sentinel.

• Introduce threadsafe parameter on get_instance, aget_instance, and their lazy variants
• Centralize locking via injection._core.common.threading.get_lock and replace direct RLock/nullcontext usages
• Extend FastAPIInject with threadsafe=True alias (InjectThreadSafe) and update stubs/tests for new default behavior

Reviewed Changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/test_singleton.py	update default None → NotImplemented assertions
tests/test_injectable.py	same update for injectable tests
tests/core/test_module.py	sync/async instance and lazy tests now expect NotImplemented
injection/ext/fastapi.pyi	add InjectThreadSafe type alias
injection/ext/fastapi.py	support threadsafe in FastAPIInject, expose InjectThreadSafe
injection/_core/common/threading.py	new get_lock(threadsafe) helper
injection/_core/scope.py	replace inline RLock/nullcontext with get_lock
injection/_core/module.py	add threadsafe args to find/get/aget/aget_lazy/get_lazy
injection/_core/common/lazy.py	remove unused alazy helper
injection/_core/common/asynchronous.py	minor formatting import change
injection/init.pyi	update stubs for threadsafe parameter and default return type

Comments suppressed due to low confidence (3)

tests/core/test_module.py:92

• Add tests that explicitly pass threadsafe=True (and False) to each getter (e.g., aget_instance, get_instance, lazy variants) to verify that concurrent access is correctly locked or unlocked.

async def test_aget_instance_with_no_injectable_return_not_implemented(

injection/_core/common/threading.py:1

• [nitpick] Consider renaming this module (e.g., lock_utils.py or synchronization.py) to avoid confusion with Python's standard threading module.

from contextlib import nullcontext

injection/ext/fastapi.pyi:7

• Add an __all__ export in this stub to include InjectThreadSafe so users of the stub file see the alias in auto‐completion and documentation.

type InjectThreadSafe[T, *Metadata] = Inject[T, *Metadata]