feat: elytra firework boost, obstacle mode, duels menu, tests
- ElytraBoost: one-shot firework boost (v*0.7+dir*0.6, FIREWORKS_SPARK,
rocket sounds) on entering ascending section + sustained thrust; Particle.
FIREWORK doesn't exist in spigot-api 1.20.4 -> FIREWORKS_SPARK
- ObstacleGenerator (client-side obstacles: PILLARS/LINES/HOLE_IN_WALL/
CIRCLE/DIAMOND via ClientBlockChanger.sendNow) + ObstacleMode + locales
- DuelsMenu (lists open duels sessions, click to join) + /parkour duels
command + tab completion + locales play.multi.duels.{name,menu_empty}
- Tests: ElytraSection/PointType/KnotDirector/SingleDuelsGenerator (15 new)
- checkstyle 0/0 (main+test), PMD 0, 41 tests pass
loki5512344
3b5d3d97d5
