Pad Start and Back ship unbound

They were mapped to the config buttons (0x37/0x36), which the 9 and 0
keys already reach from the Upper Right MFD bank. Freeing them gives
players two pad buttons to assign; bindings.txt carries the mapping as
commented example lines so the way to re-enable it is in the file.
Docs and the dist README follow.

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

MUNGA_L4/L4PADBINDINGS.cpp

@@ -376,8 +376,11 @@ namespace
 "pad DPadRight     button 0x43    # Hat Right\n"
 "pad LeftShoulder  button 0x3D    # Panic\n"
 "pad RightShoulder button 0x3F    # Throttle button (reverse)\n"
-"pad Start         button 0x37    # config 1\n"
-"pad Back          button 0x36    # config 2\n"
+"\n"
+"# Start and Back are left free - map them to whatever you want, e.g.\n"
+"# the config buttons on the Upper Right MFD:\n"
+"#pad Start        button 0x37\n"
+"#pad Back         button 0x36\n"
 "\n"
 "# ---- Upper MFD bank: the number row is the top MFD row and the\n"
 "# ---- QWERTY row is the row under it, left to right across the\n"

docs/CONTROLS.md

@@ -24,7 +24,7 @@ padaxis <src>   axis <axis> [invert] [deadzone <d>] [rate <n>]
         ______________________________________________________
        /                                                      \
       /    [Back]                                  [Start]     \
-     |     config 2                                config 1      |
+     |     unbound                                  unbound      |
      |                                                           |
      |        ,--.                                    (Y)        |
      |       ( L  )  stick X / Y                   Upper         |
@@ -51,13 +51,12 @@ padaxis <src>   axis <axis> [invert] [deadzone <d>] [rate <n>]
 | **LB** | Panic | `0x3D` |
 | **RB** | Throttle button — reverse thrust | `0x3F` |
 | D-pad | Hat: up / back / left / right (look) | `0x42` `0x41` `0x44` `0x43` |
-| **Start** | Config 1 | `0x37` |
-| **Back** | Config 2 | `0x36` |
+| **Start**, **Back** | unbound — yours to map | — |
 
-Start and Back are not extra buttons: `0x37`/`0x36` are the first two
-buttons of the Upper Right MFD's top row, which is where the config
-buttons live on the real board — so the `9` and `0` keys do the same
-thing.
+The config buttons (`0x37`/`0x36`) are the first two buttons of the
+Upper Right MFD's top row, reachable from the keyboard on `9` and `0`.
+Start and Back ship unbound so you can put anything there; the
+commented lines in `bindings.txt` show how.
 
 ---
 

pack-dist.ps1

@@ -258,7 +258,7 @@ documented default layout on first run; delete it to restore).
   A / Space / NumPad 0     joystick trigger
   RB / Alt                 reverse thrust
   DPad / arrow keys        joystick hat (look)
-  Start,Back / 9,0         config buttons
+  9 / 0 keys               config buttons (pad Start/Back left free)
   Number+letter rows       MFD bank buttons (as printed on the panel)
   F1-F12                   secondary / screen columns
   Alt+Q                    abort the mission (score banked)