Cockpit view live: V toggle, camera gate, real EyepointRotation, inside skeleton

- V toggles the authentic cockpit eyepoint <-> the chase camera.  Both eyes
  coexist; DPLEyeRenderable::Execute now writes the VIEW only when it IS
  mCamera (unconditional writes let the last-executed eye stomp the toggle).
- EyepointRotation is a real zeroed EulerAngles member on Mech (was bound to
  the shared junk attrPad -- the eye composes this attribute into the view
  EVERY frame, so the cockpit camera was rotated by garbage: the canted
  horizon, then the black screen).  The eye-slew systems write it later.
- The cockpit eye mounts at the eyepoint's REST position with a clean upright
  forward basis on the tree root (the live joint chain fed it the site tilt +
  torso pose; authentic pitch/yaw is the deferred gyro eye chain).
- The inside view swaps the player to the INSIDE skeleton mesh set
  (SkeletonType_A): 19 body segments hide, exactly one mesh remains --
  blx_cop.bgf, the authentic cockpit canopy shell around the eyepoint.  It
  currently renders as a black enclosure (the black-screen report), so it is
  HIDDEN pending its interior/punch-material rendering (BT_INSIDE_COCKPIT=1
  shows it for that work).  Damage gstates respected in both directions;
  RemakeEntity keys off the DISPLAYED skeleton.
- Dev: BT_START_INSIDE=1 starts in the cockpit view.

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

engine/MUNGA_L4/L4VIDRND.cpp

@@ -5571,7 +5571,11 @@ void
 				++dbgEyeExec;
 			}
 
-			myDevice->SetTransform(D3DTS_VIEW, &view);
+			// Only the ACTIVE camera writes the view: the BT view toggle builds
+			// BOTH the cockpit and chase eyes; an unconditional write here let
+			// whichever eye executed LAST stomp the toggled camera every frame.
+			if (myRenderer->mCamera == this)
+				myDevice->SetTransform(D3DTS_VIEW, &view);
 		myRenderer->GetMatrixStack()->Pop();
 	}
 	else if (dbgEyeExec < 8)