Show Xbox-style A/B/X/Y glyphs on the ability bar for a gamepad

Controls now tracks whether the player's last deliberate press was a
gamepad button/stick or a keyboard key/mouse click (ignoring plain
mouse motion, since the mouse still drives the camera regardless of
which device moves the bull). The HUD's ability-bar keycaps read from
that: keyboard letters normally, Xbox-style face-button glyphs while
a gamepad is in use, swapping live the moment the player switches
devices.

Godot's joypad button indices are already Xbox-position-normalized
(by SDL natively, by the browser's Standard Gamepad Mapping on web),
so the glyph mapping (button 0/1/2/3 -> A/B/X/Y) reads correctly for
any controller brand with no per-device special-casing.

Verified headlessly: labels start as the bound keyboard letters
(F/G/H/J), switch to X/A/B/Y on a synthetic joypad button press
(matching project.godot's kick/dash/slam/roll bindings), and switch
back on a keyboard press.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MXBNaEBmrYDSMcv4NgUWtV

systems/input/controls_manager.gd

@@ -27,6 +27,64 @@ func _ready() -> void:
 	_install_web_fullscreen_hook()
 
 
+# ── Active input device ──────────────────────────────────────────────────────────
+# Tracks whether the player's last deliberate input was a gamepad or keyboard/mouse, so the
+# HUD can swap its ability-bar keycaps to match whichever the player is actually holding.
+# Mouse motion is deliberately ignored — the mouse still drives the camera regardless of
+# which device is moving the bull, so panning the camera shouldn't flip the hint away from
+# gamepad glyphs. A small deadzone on joypad axes avoids stick drift/noise doing the same.
+const _JOY_AXIS_DEADZONE := 0.5
+var _last_input_is_gamepad: bool = false
+
+
+func _input(event: InputEvent) -> void:
+	if event is InputEventJoypadButton:
+		if event.pressed:
+			_last_input_is_gamepad = true
+	elif event is InputEventJoypadMotion:
+		if absf(event.axis_value) > _JOY_AXIS_DEADZONE:
+			_last_input_is_gamepad = true
+	elif event is InputEventKey:
+		if event.pressed:
+			_last_input_is_gamepad = false
+	elif event is InputEventMouseButton:
+		if event.pressed:
+			_last_input_is_gamepad = false
+
+
+## Whether the player's last button/key/stick press was on a gamepad rather than
+## keyboard/mouse. Drives which glyph set the HUD's ability keycaps show.
+func using_gamepad() -> bool:
+	return _last_input_is_gamepad
+
+
+# Godot's joypad button indices are already Xbox-position-normalized — by SDL on native, by
+# the browser's Standard Gamepad Mapping on web — so this reads correctly for any controller
+# brand (a Nintendo pad's physically-labelled "A" is button 1 here, same as "B" on Xbox).
+const _XBOX_BUTTON_GLYPHS := {
+	JOY_BUTTON_A: "A",
+	JOY_BUTTON_B: "B",
+	JOY_BUTTON_X: "X",
+	JOY_BUTTON_Y: "Y",
+}
+
+
+## Xbox-style face-button glyph ("A"/"B"/"X"/"Y") for the action's bound joypad button, or
+## "—" if it has none.
+func get_joy_button_label(action: StringName) -> String:
+	for event: InputEvent in InputMap.action_get_events(action):
+		if event is InputEventJoypadButton:
+			return _XBOX_BUTTON_GLYPHS.get(event.button_index, "?")
+	return "—"
+
+
+## Ability-bar keycap label for `action`: the bound Xbox-style face button while a gamepad
+## is in use, else the bound keyboard key — so the on-screen prompt always matches whichever
+## the player is actually holding.
+func ability_key_label(action: StringName) -> String:
+	return get_joy_button_label(action) if using_gamepad() else get_key_label(action)
+
+
 ## Godot's built-in ui_accept (menu/button confirm) ships with zero joypad bindings —
 ## checked directly: only Enter/Kp Enter/Space. ui_left/right/up/down, by contrast, do
 ## default to the D-pad and stick, which is why gamepad focus navigation on a menu works out