Expose a shared enum for lifecycle event kinds

[mcruzdev]

sdk-java currently models workflow/task lifecycle events as a set of concrete classes (WorkflowStartedEvent, TaskCompletedEvent, etc., in io.serverlessworkflow.impl.lifecycle) plus a separate class of CloudEvent-type string constants (LifecycleEvents). There's no single enum identifying "what kind of event is this" that consumers can switch/filter on without an instanceof chain or comparing against LifecycleEvents strings.

Downstream, at least two consumers in quarkiverse/quarkus-flow independently reimplement this same taxonomy as local enums:

• opentelemetry/runtime: WorkflowEventType + TaskEventType, each pairing a constant with its LifecycleEvents id and a fromEvent(WorkflowEvent) classifier via instanceof checks.
• testing (quarkus-flow-testing): EventType, a flat 16-value enum covering both workflow- and task-level events, used to classify recorded events in test assertions.

Both are hand-written mirrors of the same 16 event kinds sdk-java already defines via its event classes/LifecycleEvents constants.

Request: Expose a canonical enum (e.g. LifecycleEventType) in io.serverlessworkflow.impl.lifecycle, ideally with:

• One value per concrete WorkflowEvent subtype (workflow- and task-level).
• A way to classify an arbitrary WorkflowEvent instance to its LifecycleEventType (replacing the instanceof chains each consumer currently writes).
• A link back to the matching LifecycleEvents CE-id constant, if practical.

This would let consumers (like Quarkus Flow's opentelemetry and testing modules) drop their local duplicates and depend on a single sdk-java-owned source of truth.