Merge origin/master: the D1 relay/operator line + input remap meet the glass layer

33 master commits in (relay TCP/UDP + PySide6 operator console, CONTROLS.MAP
+XInput binding engine, camera seats, torso pitch aim, sign fixes, the 1995
manual, version stamping, 18-mech certification).  Conflicts: .gitignore +
CLAUDE.md router rows (combined).

SEMANTIC RECONCILIATION (the one real overlap): masters btinput binding
engine (ungated, CONTROLS.MAP) and the glass PadRIO (gated, bindings.txt)
would both read the keyboard/pad in a glass+PAD session.  btinput now joins
the stand-down convention: BTInputPoll yields (and BTInputSuppressKey claims
NOTHING, so authentic hotkeys flow) when an operational cockpit device owns
the input path -- BTRIODevicePresent, BT_KEY_BRIDGE force-override honored,
forced harness exempt.  One input system per mode: btinput on pod/dev
desktops, PadRIO on glass.  The mechmppr/mech4 bridge merges composed clean
(masters negate-once sign fix inside our device-gated bridge).  The D1 relay
keeps its own raw sockets by design (an alternative LAN wire; Steam and
relay are separate modes).

Verified post-merge: all 3 configs build; glass boots with [input] binding
engine standing down + PadRIO owning input (30 ticks); pod forced-walk
speedDemand=61.501 with btinput ACTIVE; 2-node loopback MP full 31/31
mission, 76/76 ticks.

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

engine/MUNGA_L4/L4CTRL.cpp

@@ -11,6 +11,15 @@
 #include "l4padrio.h"
 #endif
 
+//
+// BT port (input remap): keys claimed by a CONTROLS.MAP binding are consumed
+// by the binding engine (game/reconstructed/btinput.cpp) and must NOT also
+// reach the key-command channel -- that was the historic double-dispatch
+// ('w' drove AND selected pilot 0; F5's key-up value 0x74 aliased to the
+// 't' hotkey).  The symbol resolves from the game lib at the btl4 exe link.
+//
+extern "C" int BTInputSuppressKey(unsigned int key_value, int is_char);
+
 // #define LOCAL_TEST
 
 #if defined(LOCAL_TEST)
@@ -1572,6 +1581,11 @@ void
 				{
 					// swallowed: navigation key, not a character command
 				}
+				else if (BTInputSuppressKey((unsigned int)keyValue,
+											msg.message == WM_CHAR))
+				{
+					// swallowed: remapped by CONTROLS.MAP
+				}
 				else
 				{
 					keyboardGroup[KeyboardPC].ForceUpdate(&keyValue, mode_mask);