Torso: the TWIST goes LIVE -- electrical watchdog chain, centered crosshair, coherent controls (task #57/#58)

The MadCat torso twists, the view turns with it, and targeting follows.
Three reconstruction fronts closed:

THE ELECTRICAL WATCHDOG CHAIN (why the torso never powered up):
- PowerWatcher::UpdateWatch reconstructed (@004b181c, the REAL registered
  Performance -- PTR @0050f5fc; Ghidra missed the fn start): the watchdog
  MIRRORS the watched subsystem's electrical level (+0x278), brownout
  downgrade when gen output <= minVoltage% x rated.  @004b1804 relabeled
  ResetToInitialState (slot 10) -- the old "Simulation" tag was wrong.
- The factory watcher-CONNECT pass reconstructed (vtable slot +0x38,
  @004aee2c/@004b1a40 byte-identical, recovered from raw exe bytes):
  watchedLink.Add(roster[watchedSubsystem]) on the master node.  Was the
  SubProxy::Start() no-op -- every watchdog sat at 0 forever.
- MinVoltageScale = 0.01 (a 10-byte x87 literal @0x4b1924; was 1.0f =
  permanent brownout) and PowerWatcher's Derivation chains its REAL base
  HeatWatcher (the HeatableSubsystem stand-in broke IsDerivedFrom for the
  whole Torso/Searchlight/ThermalSight family).
- KB correction swept: derivation tag 0x50e604 = HEATWATCHER (not
  "HeatSink"); the btl4gaug heat-widget gate now tests it via the
  BTIsHeatWatcher bridge.

THE CROSSHAIR (task #58 forensics, 6-agent workflow + live probes):
- The VIEW is TORSO-MOUNTED: jointtorso -> jointeye -> siteeyepoint in
  every twist-capable .SKL; the camera + canopy ride the same hinge
  subtree through HingeRenderable's live matrix-stack compose -- ALREADY
  WORKING in the port.  The crosshair stays screen-centered (center IS
  the boresight); the twist reads on the tape carets/compass/radar.
- The real bug was the port's gBTAimX = tan(twist) slew (the falsified
  "body-mounted view" model): the camera already carried the twist, so
  the crosshair counter-slid to hull-forward and the fire ray with it.
  Deleted; the pick ray inherits the twist from the yawing eye basis.
- Two instrumentation traps documented (chase-eye-as-default-camera,
  BT_FORCE_TORSO clobbering real joints -> the hook now only fills
  unresolved ones); an over-correcting explicit eye compose was added on
  those false readings and retired the same day.

CONTROLS + REPLICATION:
- Q/E spring-center on release (the axis is a twist-RATE demand; the old
  hold-deflection model drifted forever); X also zeroes the axis and
  pulses the authentic torso Recenter (@004b6918).  M cycles control
  mode via the real CycleControlMode body.
- Torso update-record DIRECTION fixed: engine truth is Write=serialize /
  Read=apply; @004b6a78 is the READ (was mislabeled Write) and the
  missing WRITE @004b6a1c recovered from raw disasm (recordLength 0x1C,
  twist/vel/rate at +0x10/14/18) -- kills the replicant's 0xCDCDCDCD
  -140-degree ghost twist.
- Marching-ghost desync: 4 Standing-case guards zero stale reverse
  cycleSpeed (negative cadence passed the <= ZeroSpeed stop gate).
- Kill credit rerouted to the OBSERVED killer (lastInflictingID ->
  killer's player link) -- kills count, target K/D populates.

KB: subsystems.md (watcher chain), multiplayer.md (record direction),
combat-damage.md + gauges-hud.md + cockpit-view.md (torso-mounted view
re-correction), decomp-reference.md (new addresses + tag fix),
open-questions.md (dead capability-roster loops 2-4, snapshot CD read).

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

context/multiplayer.md

@@ -237,6 +237,30 @@ engine/port member.  Wire sizes verified live (0x14/0x20/0x2c/0x78).  Key mechan
   A TU-local stub type forced the `BTMapperSpeedDemandRaw(void*)` bridge (mech.cpp carries a local
   `struct MechControlsMapper` recon stub — typed cross-TU signatures mangle differently).
 
+## Subsystem update-record DIRECTION + the Torso pair (task #57, 2026-07-13) [T0/T1]
+
+**Engine semantics [T0 SIMULATE.cpp:270-297]: `WriteUpdateRecord(record, model)` PRODUCES the
+outgoing record from the object (master serialize; base sets `recordLength=sizeof`, stream
+advances by `recordLength` — variable-length records are the mechanism); `ReadUpdateRecord(record)`
+APPLIES the record into the object (replicant).** The names read backwards — do not flip them.
+Base fns in every subsystem vtable: slot 6 = 41bd34 (Read/apply), slot 7 = 41c500 (Write/produce,
+3 args).
+
+- **Torso pair:** slot 6 `@004b6a78` = `ReadUpdateRecord` (apply: lastUpdateTime clock stamp +
+  twistAtUpdate/twistVelocity/twistRate ← record +0x10/14/18). Slot 7 `@004b6a1c` =
+  `WriteUpdateRecord` — **Ghidra missed the function start**; raw-disasm recovery: chains base,
+  sets `recordLength=0x1C`, writes currentTwist/twistVelocity/twistRate → +0x10/14/18, snapshots
+  `twistAtUpdate = currentTwist`.
+- **The bug this fixed:** the old recon had the APPLY body on the WRITE virtual (and no Write at
+  all) — the master consumed its own uninitialized stream buffer (0xCDCDCDCD → twistAtUpdate =
+  −4.316e8) and never serialized twist; the replicant MadCat pinned at −140° (the "torso ghost
+  twist"). With the pair correct the replicant tracks `targetTwist = twistAtUpdate +
+  twistRate·elapsed` cleanly (cur=0 when master still). [T2 live]
+- **Residual (authentic):** the initial full-state snapshot record does NOT carry the torso
+  extras; the replicant's blind +0x10 read can pick up 0xCD fill ONCE at spawn. The binary does
+  the same read; the twist clamp contains it (on the fixed-torso BLH it pins to ±0.01° —
+  invisible). First real twist record overwrites it.
+
 ## Remaining (P6 phase 4 / Phase 7)
 The pod-LAN config (real IPs, bare-IP pilot entries); update-record velocity sourced from the body-channel
 projection (above). See [[open-questions]]. [T3]