feat(mastervega): promote V2 combat engine with performance, formation, and UI overhauls
- Promote VegaCombatV2 to the official combat engine.
- Performance: manual sqrt replaces Math.hypot, spatial grid collision avoidance, and per-side ship cap (100) with largest-remainder proportional sampling. Overflow fleets resolve via V1's cheap aggregate math.
- Combat: replace uniform grid placement with formation-aware layouts (Power Pressure, Speed Swarm) using per-ship avoidRadius. Add lead-pursuit targeting to fix gap-closing issues. Add centering force to keep battles on-screen.
- UI: add commander roster with procedural static for wiped types, move building icons below text, add direct war/peace toggle for diplomacy-incapable species.
- Test/Docs: add verifier checks for pursuit, formations, centering, spatial grid correctness, and 790-ship battle performance. Document design traps and fixes.
Brian Fertig
c105ebd23c