Bimmer's Jetpacks

• Added eleven jetpack tiers (Copper, Iron, Gold, Thorium, Onyxium, Bronze, Cobalt, Adamantite, Silver, Mithril, Prismas) with speed multipliers scaling from ~1x up to 10x.
• Jetpacks apply continuous thrust while the jetpack item is selected in the hotbar: vertical lift is capped per tier and a forward push follows the player’s look direction, so higher tiers climb and cruise faster.
• Command /jetpack <tier> hands you a tagged jetpack item (for example /jetpack copper or /jetpack prismas); items carry metadata so the tick system can identify the tier even without extra assets.
• Manifest updated to use the new main class com.playergames.bimmersjetpacks.BimmersJetpacksMod, group com.playergames.bimmersjetpacks, and jar base name bimmersjetpacks.
• Limitations: crafting recipes/textures are not bundled, and jetpacks only boost when held in the active hotbar slot; consider adding crafting, visuals, fuel, and safety toggles to refine the experience.