Torso elevation (pitch aim) wired: the pod stick's Y axis lives

The mechs could always tilt their aim up/down -- Torso models the full
vertical axis (currentElevation, rate, VerticalLimitTop/Bottom,
recenter) and EVERY 1995 control mode routes stickPosition.y into
Torso::SetAnalogElevationAxis -- but the desktop bridge hard-zeroed
stick Y, so the axis was dead on a keyboard rig.  The one pod control
the remap left unwired.

- btinput: JoystickY axis -> elevTarget/elevActive/elevAbsolute
- mech4 shim: sElev integrator (same walk/spring model as the twist;
  X recenters pitch too via gBTElevRecenter)
- mechmppr bridge: feeds stickPosition.y every bridged frame (the old
  unconditional zero removed); both mode branches covered
- CONTROLS.MAP (+ numpad profile + compiled default): R/F = aim
  up/down, pad LeftStickY = elevation (was unused)
- torso.hpp: CurrentElevation()/ElevationVelocity() accessors (diag)
- [mppr] trace gains stickY (note: the trace reads AFTER the next
  frame's device push re-zeroes the stick -- input flows regardless)

Verified live: R held -> torso elevation climbs at the authored rate
and clamps at 0.349066 rad = exactly 20.0 deg (the Blackhawk's
VerticalLimitTop); release holds the aim.  The eyepoint correctly
stays level -- pitch aims the GUNS and reads on the HUD's vertical
elevation tape, as in the pod.

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

game/reconstructed/mechmppr.cpp

@@ -719,6 +719,14 @@ void
 					gBTModeCycle = 0;
 					CycleControlModeNow();
 				}
+				// TORSO ELEVATION (pitch): the pod stick's Y axis -- every
+				// control mode routes stickPosition.y into
+				// Torso::SetAnalogElevationAxis below, so the bridge feeds
+				// it in BOTH branches (keys R/F or a pad stick via btinput).
+				{
+					extern float gBTElevAxis;
+					stickPosition.y = gBTElevAxis;
+				}
 				if (controlMode == BasicMode)
 				{
 					stickPosition.x = key_turn;
@@ -751,7 +759,8 @@ void
 					}
 				}
 			}
-			stickPosition.y  = 0.0f;
+			// (stickPosition.y no longer zeroed here -- the bridge above
+			// feeds the elevation axis every bridged frame, 2026-07-18)
 		}
 	}
 
@@ -822,6 +831,15 @@ void
 		{
 			torso->SetAnalogElevationAxis(stick_y);	// raw torso+0x1f4 (500)
 			torso->SetAnalogTwistAxis(0.0f);		// raw torso+0x1f0
+			if (getenv("BT_INPUT_LOG"))
+			{
+				static float s_eacc2 = 0.0f; s_eacc2 += time_slice;
+				if (s_eacc2 >= 1.0f) { s_eacc2 = 0.0f;
+					DEBUG_STREAM << "[input] mppr elev in=" << stick_y
+						<< " torsoElev=" << torso->CurrentElevation()
+						<< " vel=" << torso->ElevationVelocity()
+						<< "\n" << std::flush; }
+			}
 		}
 		if (cockpit)
 		{