Toggle the first-person camera with a right thumbstick click

Clicking the right thumbstick flips first person exactly as the F10
checkbox does, and saves it the same way. It works on the VR controllers
in either presentation (with a short tick on the right controller) and on
any other gamepad while VR is running. It never reached the game: SDL's
stick click only lands in Aurora's extended buttons.

A click counts on release, and only if the left thumbstick stayed up and
the headset settings panel stayed closed throughout, so the two-thumbstick
panel chord in gamepad mode never toggles the camera. A gamepad whose
right stick click is bound to a GameCube control on its port, as a button
or in an input expression, keeps it for the game. The XR side only posts
a request; the toggle itself runs on the game thread with the checkbox.

[vr] first_person_toggle_click (default true) and a checkbox under the
camera toggle turn the click off. mkw_vr_camera_toggle_tests covers the
click rule.

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

OPENXR.md

@@ -48,6 +48,7 @@ hud_virtual_screen = true
 stop_at_display_copy = true
 skip_copy_clears = true
 first_person = false
+first_person_toggle_click = true
 first_person_seat = "cockpit"
 cockpit_units_per_meter = 100.0
 first_person_units_per_meter = 50.0
@@ -173,11 +174,12 @@ Touch controllers. The port is served through KPAD like a Bluetooth remote
 | Left trigger | Z |
 | Left grip | C |
 | Left Y | Settings panel (not a Wii button) |
+| Right stick click | First-person camera on / off (not a Wii button) |
 | Right controller motion and aim | Wii Remote accelerometer and pointer |
 | Left controller motion | Nunchuk accelerometer |
 
-Analog inputs count as pressed past half travel. Right B, right stick left / right and the stick
-clicks are unbound, and no controller button presses HOME. The game's Wii Remote rumble vibrates
+Analog inputs count as pressed past half travel. Right B, right stick left / right and the left
+stick click are unbound, and no controller button presses HOME. The game's Wii Remote rumble vibrates
 both controllers, subject to the ordinary controller-vibration switch.
 
 **Motion.** Each XR frame the aim and grip poses are located at the measured current time
@@ -221,7 +223,7 @@ own motion detection still reads them, so a sharp enough turn can read as a shak
 A/B → South/East, X/Y → West/North, index triggers → trigger axes, grips → shoulders, thumbsticks
 → sticks (clicks → stick buttons), left menu → Start. Every binding in the F10 controller menu
 applies. Left Y is GameCube Y here, so clicking both thumbsticks together opens the settings panel
-instead.
+instead. The right thumbstick click on its own still toggles the first-person camera.
 
 Bindings are suggested for `oculus/touch_controller` (Quest 2, 3 and Pro) and
 `khr/simple_controller`. `mkw_vr_wii_remote_tests` checks the accelerometer frame, the pointer
@@ -289,6 +291,17 @@ to the local driver's head instead, at one of two seats:
 
 Both are a matter of taste rather than properties of the game, so the F10 bar exposes them.
 
+**Toggling it from a controller.** Clicking the right thumbstick turns first person on or off
+exactly as the F10 checkbox does, and the choice is saved the same way. It works on the VR
+controllers in either presentation (the right controller gives a short tick), and on any other
+gamepad while VR is running. A click counts on release, and only if the left thumbstick stayed up
+and the settings panel stayed closed throughout, so clicking both thumbsticks to open the panel in
+gamepad mode never toggles the camera. A gamepad whose right thumbstick click is bound to a
+GameCube control on its port, as a button or in an input expression, keeps it for the game instead.
+Toggled in a menu, the change applies from the next race. `first_person_toggle_click = false`, or
+the F10 checkbox under the camera toggle, turns the click off. `mkw_vr_camera_toggle_tests` covers
+the click rule.
+
 The kart is selected through the game's local-screen-to-racer mapping, including online races
 where your racer is not slot zero. First person requires a locally controlled racer; spectating
 another racer keeps the game's own camera.