Allow recursive container calls from factory functions

[clue]

This changeset allows recursive container calls from factory functions for any variables or classes. On its own, this is rarely useful as the Container has no public API exposed at the moment. This is mostly done as an internal preparation at the moment, but may be exposed as part of our public API that allows us to reuse this logic for more classes in a follow-up.

$_ENV['X_FOO'] = 'foo';

$container = new Container([
    'X_FOO' => fn(Container $container): string => $container->getEnv('X_FOO') ?? 'default'
]);

assert($container->getEnv('X_FOO') === 'foo');

Builds on top of #290, #289, #288, #96 and others

[Copilot]

Pull request overview

Enables factory functions in Container to make recursive container calls (e.g., getEnv() / getObject()) by temporarily removing the active factory entry during invocation, so recursion can fall back to global env or default autowiring instead of immediately recursing into the same factory.

Changes:

• Update Container::loadObject() to temporarily unset() the factory config entry while invoking factory closures.
• Small internal refactor in loadVariable() to inline param loading/invocation.
• Update/add tests to cover recursive getEnv() and recursive getObject() behavior and adjust expected error messages.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
src/Container.php	Temporarily unsets factory entries during closure invocation to permit recursive lookups; minor invocation refactor in variable loading.
tests/ContainerTest.php	Removes old “recursive class” failure test and adds new test coverage for recursive getEnv()/getObject() patterns; updates an assertion message.

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[Copilot]

The comment says the factory is unset "to allow loading recursive variables from environment", but in this branch it's also enabling recursive getObject()/container lookups from within object factories. Updating the comment to reflect the broader intent would avoid confusion for future maintainers.

[Copilot]

New test method name uses singular "Return" but the existing naming pattern in this file appears to be "testGetObjectReturns…". Renaming to "testGetObjectReturnsDefaultStdClassInstanceWhenFactoryFunctionHasRecursiveArgument" keeps test names consistent and easier to search/scan.