#148: restore the ENGINE's replicant instance-branch in the Mech subsystem tick

Correct on its own merits as a fidelity fix; it is NOT the cause of #148, and
I am not claiming it is.

Entity::Perform (ENTITY.cpp:733-793, real engine source [T0]) picks the
executable predicate BY INSTANCE:

    if (GetInstance() != ReplicantInstance)  IsNonReplicantExecutable()
    else                                     IsReplicantExecutable()

and the two differ exactly on the replicant case (SIMULATE.h:195-206):

    NonReplicant : (flags & DontExecuteFlag) == 0
    Replicant    : (flags & DontExecuteFlag) == 0 || lastUpdate >= lastPerformance

`ExecuteOnUpdate()` SETS DontExecuteFlag -- it means "do not tick me every
frame, tick me when an UPDATE ARRIVES".  Mech's reconstructed tick loop used
the NonReplicant predicate for EVERY mech, dropping the branch, so on a
replicant any ExecuteOnUpdate subsystem could never run however many records
arrived.  Restored.

Measured: it does NOT move #148 (first TorsoCopySimulation call 1014 -> 1006,
noise).  So the torso's own flag was not the gate.  Keeping it because the
engine source is unambiguous about what the loop is supposed to do.

WHAT #148 ACTUALLY IS, now much better characterised:

* The record CADENCE is authentic -- my original "only 13 records" framing was
  wrong.  Payloads are the sweep EXTREMES with `rate` flipping sign each time
  (atUpd 0.0437, 2.3558, -2.3928, 2.3854, ...): the master sends on RATE
  CHANGE and the peer dead-reckons `atUpd + rate * elapsed` between them.  12
  records for 12 direction reversals is correct, not starved.

* The real defect is that the peer's copy torso PERFORMANCE does not run at
  all until log line ~1006, while its first record arrived at line 205 -- ~800
  lines of correctly-replicated twist integrated by nobody.  The first tick
  coincides with the replicant's MODEL bring-up, not with record arrival:

      [loadclips] end: fScale=0.8 ... hasGimpClips=1
      [clipfix] mech 05769358 -> EXTERIOR (lean)
      [torso] PushTwist COPY node=057A3C68 type=1 twist=-1.52319

  so the gate is above the subsystem level, in replicant model/clip init.
  Not yet found; #148 stays OPEN.

Also: [torso-copy] logs on call #0 (s_cl++ % 120), so its first line IS the
first Performance call -- that is what makes the 205-vs-1006 gap readable, and
it is why the earlier "first copy currentTwist != 0 at 1016" reading was a
SAMPLING artifact, not a measurement of when the twist started.

Probe additions kept: [torso-copy] now prints limL/limR/enab (which ruled out
the ComputeTargetTwist clamp -- limits load correctly at +/-2.44346 on the
copy), and [launchframe] now prints the shooter's live torso twist so
twistDelta and its driver sit on the SAME line.  That pairing is what proved
#141 is fully fixed: every zero-twistDelta peer launch reads liveTwist=0, and
the first launch with liveTwist=-1.84061 reads twistDelta=-1.83813.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018SgmXGNMXavXiafKXf9MDC

game/reconstructed/torso.cpp

@@ -823,6 +823,13 @@ void
 				<< " vel=" << twistVelocity
 				<< " lastUpd=" << lastUpdateTime
 				<< " now=" << GetCurrentTime()
+				// #148: ComputeTargetTwist ends in Min(limitLeft)/Max(limitRight).
+				// If the COPY's limits never loaded they are 0/0, which pins
+				// targetTwist to EXACTLY 0 no matter what the record carried --
+				// which is what a peer stuck at zero twist would look like.
+				<< " limL=" << horizontalLimitLeft
+				<< " limR=" << horizontalLimitRight
+				<< " enab=" << (int)horizontalEnabled
 				<< " copy=" << (int)isDamagedCopy << std::endl;
 	}
 }