OpenCode global events, durable settlement, and subscriber bounds

OpenCode publishes application events globally with workspace metadata so consumers can filter across instances; EventV2Bridge is the compatibility boundary into GlobalBus. Replayable state uses exactly one durable terminal settlement rather than reconstruction from progress deltas. session.tool.success, session.tool.failed, and session.compaction.ended settle durable state; reasoning and compaction deltas are live-only. SSE consumers must filter before enqueue and use queues bounded by bytes/events: finalizers alone do not prevent stalled subscribers from retaining arbitrary payloads.