T13440 di remove instance

[niden]

Hello!

• Type: new feature
• Link to issue: [NFR] Make shared instances removable #13440

In raising this pull request, I confirm the following:

• I have read and understood the Contributing Guidelines
• I have checked that another pull request for this purpose does not exist
• I wrote some tests for this PR
• I have updated the relevant CHANGELOG
• I have created a PR for the documentation about this change

Added Phalcon\Di\Di::hasShared(string $name): bool and Phalcon\Di\Di::removeShared(string $name): void (also declared on Phalcon\Di\DiInterface) to operate on the shared-instance cache independently of the service-definition registry. hasShared() reports whether getShared() has already materialized an instance for the given name (in contrast to has(), which reports on the definition registry). removeShared() drops the cached instance — both from Di::$sharedInstances and from the Service object's internal sharedInstance field — without removing the service definition, so the next getShared() call rebuilds a fresh instance. Use case: fork-based multi-process workers that need to discard the parent's inherited resource handle (DB connection, etc.) without re-registering the service. Both methods are alias-aware

Thanks