Reticle Execute @004cdcf0 RECOVERED: every HUD instrument now live (task #37)

The one un-exported gap in the reticle chain, read via capstone
(tools/disas2.py; the annotated disasm preserved at
reference/decomp/reticle_execute_004cdcf0.disasm.txt). Draw() is now a
transcription of the real per-frame logic, and the HUD attr-table names
(hud.hpp ids 4/5/6/8/A/B/C/D) are CONFIRMED by their Execute usage:

- Range ladder: BAR from ladder-top to the caret + caret translate.
- The bottom 21-tick tape is the TORSO-TWIST indicator (NOT heading):
  deflection = -/+(span/2) x (RotationOfTorsoHorizontal / twist limit),
  attrs 4/5/6. Fixed-torso BLH reads centred -- authentic static.
- The circle-with-stem is the COMPASS (attr 0xD, rad->deg rotation) at
  (botX, botY - 3*tickMajor - 0.03), with the THREAT trail (attr 0xC)
  in its rotated frame: 0.05-unit attack-direction marks, fresh < 2s
  red, expiring at 6s. Port feed: player TakeDamage pushes the impact
  direction (dormant vs the passive test dummy).
- Pips (composed into subB6): hidden when destroyed (attr 1 == 1), LIT
  when the fire cycle is LOADED (attr 0x1c == 2; port source
  rechargeLevel >= 1) else the dark charging ring; filtered by the
  weapon-GROUP bits (weaponMode & elementMask&0xF). Range plays NO part
  (the stored TargetWithinRange slots are never read by Execute).
- Lock ring: subB9 at frame centre SPINNING 4 deg/frame while locked
  ([0x9d] is the spin matrix, not a heading list).
- Target HOTBOX: a rectangle hugging the projected extents (x+-4 around
  the top-centre hotbox point, +1/-11.5 vertical; baked K=2.8145 -- the
  port projects through the live per-axis projection), switching to the
  edge arrows past +-1.6 or behind (BTProjectHotBox, L4VIDEO).
- Reticle state Off/On + PrimaryHudOn full-HUD/simple-X switch, aim
  translate on slew move, 3D marker + PNAME player-name mesh identified
  (chain still deferred).

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

game/reconstructed/mech.cpp

@@ -554,6 +554,19 @@ void
 	// WRITTEN -- a reconstruction gap; the natural authentic write site is
 	// this handler (every damage message carries the inflictor).  [T3]
 	lastInflictingID = message->inflictingEntity;
+
+	// THREAT feed (task #37, the recovered reticle Execute's ThreatVector
+	// attr 0xC): when the PLAYER takes a hit, push the attack direction --
+	// world (x,z) from the mech toward the impact point -- onto the HUD's
+	// compass-rose threat trail (fresh marks red, fading over 6s).
+	if (application != 0 && (Entity *)this == application->GetViewpointEntity())
+	{
+		extern void BTPushHudThreat(float wx, float wz);
+		BTPushHudThreat(
+			(float)(message->damageData.impactPoint.x - localOrigin.linearPosition.x),
+			(float)(message->damageData.impactPoint.z - localOrigin.linearPosition.z));
+	}
+
 	DamageLookupTable *table = (DamageLookupTable *)damageLookupTable;	// named member (Wword absorbs!)
 	if (message->invalidDamageZone && table != 0)
 	{