[client] input: synchronize host lock state over LGMP

Cache native keyboard lock state across input-provider transitions and
reconcile it with HID LED feedback over LGMP.

Project raw and corrective lock-key transitions through the reliable
input FIFO, defer correction until outstanding transitions settle, and
recover from delayed or missing feedback without double toggling.

client/include/input.h

@@ -53,6 +53,7 @@ void lgInput_setAvailabilityListener(
 bool lgInput_keyDown(int key);
 bool lgInput_keyUp(int key);
 bool lgInput_keyboardLEDs(bool numLock, bool capsLock, bool scrollLock);
+void lgInput_setKeyboardLEDsSync(bool enable);
 void lgInput_releaseKeys(void);
 void lgInput_releaseButtons(void);
 /* Release all tracked keyboard and mouse button state under one active-input