- New NebulaLightning visual: jagged edge-to-edge bolt with branches,
strobed in the gas base/accent colors, plus a soft distant thunder clap
- Pure seeded math (boltStrobe, strikeCycle, boltShape) in SystemEffectsMath,
Node-tested for determinism and shape correctness
- Wired into GameScene create/update/destroy lifecycle
- Config block in data/systems.json types.nebula.effect.lightning; docs
updated with tuning notes and smoke-game probe (?lightning=1&forceStrike=1)