- defenseHp is now a pure per-battle ammo gauge (one full-strength
shot per planetDefensePerShot points, remainder as fractional shot)
instead of in-battle damage tracking; no longer written back after
battle outcome
- Planet now has a real range limit (planetRange, 1200) — previously
the only entity with no range check at all
- Per-shot damage scales with the defending empire's best known weapon
tech (weaponAvgDmg) instead of a flat HP-proportion curve
- defenseHp is only wiped to 0 when the planet is actually DESTROYED,
fixing the bug where a defeated planet could be re-attacked multiple
times in one turn with full strength each time
- Added combat config: planetDefensePerShot (5), planetShotDamageMult (1)
- Added combatV2 config: planetRange (1200)
- Comprehensive tests for range gating, shot formula, ammo exhaustion,
multi-battle-same-turn fix, and tech-scaled damage
