v0.4.3 — SwarmFake actor assertions

Added

• SwarmFake gains three new actor assertions (#34): assertDispatchedWithActor(Actor|string|callable), assertDispatchedWithAnyActor(), and assertNeverDispatchedWithActor(). Helpers inspect every dispatch bucket (run, queue, durable, stream) for a RunContext whose metadata.actor matches. Bare-string and structured-array tasks never carry an actor — pass an explicit RunContext::fromTask($task)->withActor(...) when you want the binding to be visible to SwarmFake.
• New ## Testing Audit Extension Points section in docs/testing.md documents the three patterns for testing the four v0.4 audit-extension contracts (CapturePolicy, SinkFailureHandler, SwarmAuditSigner, ActorResolver): unit-test the contract directly, bind a recording SwarmAuditSink for end-to-end audit checks, or use 'halt' failure policy to assert run-level halt behavior. Worked examples reference the package's own tests/Unit/Audit/ suite.
• New ## Asserting Actor Binding section in docs/testing.md walks through the three new SwarmFake assertions with code samples, including the Context::add('swarm:actor', ...) + explicit withActor() pattern for tests that bridge the Laravel Context facade and SwarmFake.

Changed

• Reframed the original #34 issue scope. The issue asked for assertions on all four v0.4 audit extension contracts, but only Actor has a dispatch-time signal SwarmFake can observe — the other three are runtime concerns inside the audit dispatcher, a path SwarmFake intentionally skips. The new docs section captures the three contracts' actual test patterns instead of pretending SwarmFake covers them.