src/orchestrator/events.ts — run event bus + wire contract

Purpose

run() never calls a Logger directly: every log.X(...) emits a RunEvent through busLogger onto an in-process bus; the terminal renderer is just the always-on subscriber. Web/TUI/MCP surfaces attach as additional subscribers with zero orchestrator changes.

Public surface

• createEventBus() — synchronous, order-preserving fan-out.
• busLogger(bus) — Logger-shaped facade that emits events.
• terminalSubscriber(sink) — drives a concrete renderer.
• WireEvent + toWireEvent — the SERIALIZABLE projection (task ids instead of node back-refs; bigint ns as decimal strings) used by serve delegation, dev sockets, and event sinks.

Invariants

• Fan-out is synchronous, so terminal output is byte-identical to the pre-bus direct-call era.
• Raw TaskOutcomes are NOT serializable (bigint + graph back-refs); anything crossing a process boundary goes through toWireEvent.