Controls: the keyboard bridges STAND DOWN for a live device (step 2c)

New engine query BTRIODevicePresent() (L4CTRL.cpp, ungated -- pod-correct for
the serial RIO too): device exists AND IsOperational().  Both dev input
bridges -- the mech4.cpp mapper-attr writes and the mechmppr.cpp BT_KEY_BRIDGE
block -- now gate their WRITES on it: BT_KEY_BRIDGE unset = auto (bridge only
when no device), 0 = force off (the documented pod setting, honored), else
force on.  The BT_FORCE_THROTTLE headless harness always rides the bridge.
The mapper demand READ (turn = turnDemand) always runs.

Verified live (glass build, PAD): OS-injected LSHIFT hold slews the PadRIO
throttle 0 -> 0.33 -> 1.0 with pre==thr every frame -- the value arrives via
the ENGINE push through the streamed .CTL binding, not the bridge -- and
speedDemand=61.501 comes out of the authentic InterpretControls.

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

engine/MUNGA_L4/L4CTRL.cpp

@@ -1174,6 +1174,29 @@ void
 }
 
 //
+//############################################################################
+// Game-side device query (glass-cockpit step 2c): True when a real cockpit
+// device (serial RIO on the pod, PadRIO under BT_GLASS) is present AND
+// delivering input.  The game's dev keyboard input bridges (mech4.cpp,
+// mechmppr.cpp) stand down then -- they would clobber the device's engine
+// push every frame.  This automates the documented pod intent
+// ("BT_KEY_BRIDGE=0 to disable on pods").
+//############################################################################
+//
+int
+	BTRIODevicePresent(void)
+{
+	if (application == NULL)
+	{
+		return 0;
+	}
+	LBE4ControlsManager *controls =
+		(LBE4ControlsManager *)application->GetControlsManager();
+	return controls != NULL
+		&& controls->rioPointer != NULL
+		&& controls->rioPointer->IsOperational();
+}
+
 //############################################################################
 // Execute
 //

game/reconstructed/mech4.cpp

@@ -3141,15 +3141,28 @@ void
 		MechControlsMapper *mppr = MappingMapper();			// roster slot 0 (task #7)
 		if (s_realControls && mppr != 0)
 		{
+			// STAND-DOWN (glass-cockpit step 2c): with a LIVE cockpit device
+			// (serial RIO on the pod, PadRIO on a glass build) the engine
+			// controls push owns these attributes via the streamed .CTL
+			// bindings -- the keyboard writes below would clobber the device
+			// every frame.  BT_KEY_BRIDGE: unset = auto (bridge active only
+			// with no device), "0" = force off, anything else = force on.
+			extern int BTRIODevicePresent(void);
+			static const char *s_kbEnv = getenv("BT_KEY_BRIDGE");
+			int bridge_writes = s_kbEnv ? (*s_kbEnv != '0')
+				: (gBTDrive.forced || !BTRIODevicePresent());
 			// Diagnostic: what the ENGINE controls push left in the attribute since
 			// our last write (a stale device element overwriting the bridge shows
 			// here as pre != our previous write).
 			float preThrottle = mppr->throttlePosition;
 			(void)preThrottle;
+			if (bridge_writes)
+			{
 			mppr->throttlePosition = (throttle >= 0.0f) ? throttle : -throttle;
 			mppr->reverseThrust    = (throttle < 0.0f) ? 1 : 0;	// ControlsButton: >=1 engaged
 			mppr->stickPosition.x  = turn;						// Basic mode: turn = stick yaw
 			mppr->stickPosition.y  = 0.0f;
+			}
 			// Consume the PREVIOUS frame's interpreted demands (the mapper ticks in
 			// the roster walk after this block -- one frame of input latency).
 			// turnDemand is the mode-shaped steering; speedDemand (world u/s, sign =

game/reconstructed/mechmppr.cpp

@@ -612,8 +612,16 @@ void
 	// authoritative on the dev box.  Interpretation below stays 100% authentic.
 	//
 	{
-		static const int s_keyBridge =
-			(getenv("BT_KEY_BRIDGE") == 0 || *getenv("BT_KEY_BRIDGE") != '0');
+		// STAND-DOWN (glass-cockpit step 2c): BT_KEY_BRIDGE unset = AUTO --
+		// the bridge runs only when NO live cockpit device (serial RIO /
+		// PadRIO) owns these attributes through the engine push; "0" =
+		// force off (the old pod setting, still honored), anything else =
+		// force on.  The headless forced harness (BT_FORCE_THROTTLE)
+		// always rides the bridge.
+		extern int BTRIODevicePresent(void);
+		static const char *s_kbEnv = getenv("BT_KEY_BRIDGE");
+		int s_keyBridge = s_kbEnv ? (*s_kbEnv != '0')
+			: (gBTDrive.forced || !BTRIODevicePresent());
 		if (s_keyBridge && mech != 0 && application != 0
 			&& (Entity *)mech == application->GetViewpointEntity())
 		{