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>

game/reconstructed/mech4.cpp

@@ -1207,6 +1207,17 @@ void
 					const int xNow = focused && (pAsync('X') & dn) ? 1 : 0;
 					if (xNow && !sPrevX) gBTDrive.allStop = 1;	// edge -> one all-stop
 					sPrevX = xNow;
+					// V: toggle the view between the authentic COCKPIT eyepoint
+					// (the pod's only view) and the external chase camera.
+					static int sPrevV = 0, sViewInside = 0;
+					const int vNow = focused && (pAsync('V') & dn) ? 1 : 0;
+					if (vNow && !sPrevV)
+					{
+						sViewInside = !sViewInside;
+						extern void BTSetViewInside(int inside);
+						BTSetViewInside(sViewInside);
+					}
+					sPrevV = vNow;
 				}
 			}