Fix aircraft not working on custom vehicle models

[TheCrazy17]

Summary

Planes, helicopters and Vortex cloned with engineRequestModel now behave like the model they were cloned from. Full breakdown by vehicle below.

Model	Fixes
Hydra	Guns, homing missiles, gunsight, missile lock-on reticle & camera, VTOL nozzle turn + thrust vectoring (plane and hover mode), ground wheel steering exemption, door, jet engine sound, landing gear, adjustable nozzle-angle readout
Hunter	Minigun, missile lock, gunsight, door
Rustler	Guns, door, landing gear
Cropduster	Door, smoke trail
Shamal	Door, jet engine sound, landing gear
Nevada	Door, landing gear
Stunt Plane	Door / rear wheel visibility, smoke trail toggle key, smoke particle spawn
AT-400	Landing gear, boarding/exit stair alignment, door collision model, exit door-height exemption, G-key closest-car targeting distance, jumbo shadow, jet engine sound
Andromada	Loading ramp physics, door, jet engine sound, jumbo shadow, cargo door creak sound, landing gear
Vortex	Traction/hover feel, suspension cushion, ground-rest exemption, steering, camera distance, thrust and turn damping, flyer-collision exemption, car-style crash damage, fan FX, hovercraft audio flag, engine sound, physics keep-alive, door panel
RC Baron	Flight (thrust/control response), camera, engine sound
Sea Sparrow	Water landing physics, buoyancy, mounted gun spread
Leviathan	Buoyancy constants, physics keep-alive
Skimmer	Boat physics (capsize recovery, water-landing damping, aquaplaning, steering, water drag), buoyancy constants, wheel status, splash FX, wake trail, propeller-spin render, boat camera (mode selection + framing), first-person culling
Police Maverick	Native searchlight (horn key)
RC Bandit, RC Raider, RC Goblin	Engine sound
RC Tiger	Engine sound, mounted gun spread
Sparrow	Mounted-gun-spread resolver now recognises it (shares code with Sea Sparrow)

Stock vehicles are untouched; every hook resolves a custom model ID back to the one it was cloned from and falls through unchanged otherwise.

Motivation

Part of #1861. This started much smaller: get the Hunter's minigun and the Hydra's missiles firing on a cloned model. Testing that surfaced a much bigger problem; nothing about a cloned aircraft matches native code, since every system that decides what a vehicle is (the flight model, the weapon code, the audio entity, the constructors, the cameras) does it with a hardcoded model ID comparison, and a clone made with engineRequestModel carries an ID of its own. Fixing only the guns would have shipped a plane that could shoot but couldn't take off right, had no engine sound, and used the wrong camera.

It wasn't the plan to turn this into a PR this size. Splitting it up was considered, but a lot of these fixes share a resolved model ID across several native compares in the same function, a seven-way door switch collapsing into one resolve, for example; doing that piecemeal across separate PRs would have meant reopening already-merged code and reverifying register liveness a second time on the same instructions, which is exactly the kind of change that's easy to get subtly wrong in inline assembly. So the PR grew to cover the whole class of bug in one pass instead, merging every hook that could be merged to keep the total line count as small as the scope allows. It ended up being several days of work, most of it disassembly verification rather than writing code.

One thing worth calling out: the Vortex is implemented natively as a CPlane, not a boat class, despite behaving like a hovercraft in gameplay. That's why several of its fixes live in the same plane-specific functions as the Hydra's, and why a few hooks below end up fixing the Vortex and the Skimmer together off the same shared load even though they're unrelated vehicle types on paper.

Test plan

Tested with the attached Lua script (spawns a clone of each vehicle behind a chat command, e.g. /sethydra, /setvortex) against a stock instance of the same model, side by side, for every vehicle listed in the table above. Confirmed stock vehicles behave exactly as before the change.

aircraft-test.zip

Checklist

• Your code should follow the coding guidelines.
• Smaller pull requests are easier to review. If your pull request is beefy, your pull request should be reviewable commit-by-commit.