Flexytra

Added Added the Flexytra wearable gliding item. Added shaped crafting recipe using Feathers, Wool, and Lead. Added Elytra-compatible gliding. Added Firework Rocket boosting. Added configurable flight enable/disable control. Added Nether flight configuration. Added End flight configuration. Added custom-dimension flight configuration. Added configurable flight durability interval. Added configurable Firework Rocket boost frequency. Added boost-state tracking. Added flight-state tracking API. Added flight start and stop events. Added durability events. Added rocket-boost validation system. Added Firework Rocket item tag. Added client boost feedback networking. Added server-authoritative configuration. Added Flexytra tooltip and item resources. Added MIT licensing and MineGamer attribution.