v0.2.3

feat: advertise $harness/* capabilities (animus-protocol v0.1.13)

Bump protocol pin v0.1.11 -> v0.1.13 and switch to provider_main_with_capabilities
to advertise $harness/cancellation-loop-v2.

Verification: codex session manager terminates the subprocess on cancel and
the wrapper emits SessionEvent::Error{recoverable:false}, which surfaces as
AgentNotification::Error{recoverable:false} - the alternative cancel signal
the plugin-testkit harness accepts alongside REQUEST_CANCELLED (-32002).

Bumps plugin version 0.2.2 -> 0.2.3.