PHP SDK 3.0.0

PHP SDK 3 fixes mutable state leaking between attributed workflow invocations. Workflows receive fresh instances for execution, replay, queries and updates, while application-owned dependencies retain their identity.

Migration from SDK 2:

• Register attributed workflows by class or with WorkflowFactory; replace prebuilt workflow objects.
• Use transient PSR-11 workflow bindings. Laravel and Symfony integrations construct fresh workflow instances.
• Keep workflow constructors free of external side effects: construction repeats during replay and request handling.
• Preserve deterministic workflow code and recorded collaborator identities when migrating existing histories.

See the migration guide and SDK reference. PHP and Server compatibility floors are unchanged. Existing SDK-2 installations retain their selected version until explicitly upgraded.

Release source, qualification and installed-package acceptance are recorded in PR #111 and issue #16.