Aircraft destruction

A 6.2-second local loss cinematic, called by shared.finish only when the aircraft hull reaches zero. Cockpit impact flash and sparks lead into a trailing exterior camera and five independently tumbling pieces partitioned from the actual fighter mesh. Fire and smoke follow the fuselage; water impacts spray and sink, terrain impacts explode and settle. The sortie remains defeated and the mission director delays recording until the sequence ends. Enter or the debrief button skips after one second. Restart and teardown release owned particles, effects and entities and restore cockpit visibility.

Dependencies: the existing fighter material, game.combat.wreck meshes (reproducible with design/bake-wreck.luau), builtin impact/explosion effects, loss smoke/fire shaders and materials, mission terrain height field, cockpit camera and loss UI. Lifecycle and outcome checks: design/verify-destruction.luau.