Mirrors HeadlessFixture.NewNetworkEmitBattle wiring (opponent seating, leader
life, card templates, deck seeding) minus the emit-only RealTimeNetworkAgent
scaffolding (shadow only receives). Probe passed first run — M13 already filled
the network-mgr construction gaps. No Engine/ edits; drift clean.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>