BT410 Phase 5.3.18: flying missiles -- spawn/home/detonate LIVE, teardown open

The Missile entity family is reconstructed: Projectile : Mover gets a real
make-path ctor; Missile hosts the Seeker + MissleThruster roster (the
AUTHENTIC surviving SEEKER.HPP / MISTHRST.HPP interfaces -- the 1995
misspelling included) and flies the binary's guided integrator (@004bef78):
age/lifetime, seeker re-lead with the decoded loft constants
(200/50/300/0.1), thruster burn, steering (gain 4.0, deadband 1e-4), and
the proximity fuse delivering the cluster damage ONCE with the launcher as
inflictor.  Live-verified end-to-end: LAUNCH -> flight telemetry (thruster
visibly accelerating) -> DETONATE on the target ~0.9s out.

OPEN: the first ~Missile off the death row completes, then the frame
page-faults with EIP in the heap -- the first entity/subsystem teardown the
reconstructed sim has ever run.  The spawn path is therefore OPT-IN
(BT_MISSILE_FLIGHT=1); default SRM delivery stays the 5.3.18a instant-hit
cluster (verified 1:1, zero exceptions).  Forensics + engine truths
(SearchList crashes on non-directory ids; MakeMessages need FAMILY resource
ids; explosionModelFile is a model-list INDEX) in MISSILE.NOTES.md.

Also fixed on the way: the Subsystem NAME ctor left damageZone
UNINITIALIZED (latent garbage for every name-built subsystem).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

restoration/source410/BT/MECHWEAP.CPP

@@ -135,6 +135,7 @@ MechWeapon::MechWeapon(
 	damageAmount			= subsystem_resource->damageAmount;
 	damageType				= subsystem_resource->damageType;
 	heatCostToFire			= subsystem_resource->heatCostToFire;
+	explosionResourceID		= subsystem_resource->explosionModelFile;
 	targetWithinRange		= False;
 
 	damageData.damageType	= damageType;