Add 3X game speed and R2/L2 shoulder button speed hotkeys

Add 3X as a speed option between 2X and 4X in GameSpeed.LEVELS (#677).

Add controller hotkeys: rightshoulder (R2) cycles speed up through the
level list, leftshoulder (L2) cycles speed down. Keyboard equivalent
is hotkey 1 (cycles up). All hotkeys are gated during transitions,
scripted cutscenes, and link play (same guards as the color hotkey
at key 2).

The _cycleSpeed helper wraps the save-options update with the same
busy/overworld guard used by the existing color-cycle hotkey.

Fixes #677

src/core/Game.lua

@@ -509,6 +509,24 @@ function Game:wheelmoved(_, dy)
   end
 end
 
+function Game:_cycleSpeed(dir)
+  if not (self.save and self.save.options) then return end
+  local busy
+  local ow = self.overworld
+  if ow then
+    local top = self.stack:top()
+    busy = ow.transitioning
+      or (top == ow and (
+           (ow.runner and ow.runner.isRunning and ow.runner:isRunning())
+        or (ow.scriptMoves and #ow.scriptMoves > 0)
+        or ow.engaging or ow.emote))
+  end
+  if busy then return end
+  local GameSpeed = require("src.core.GameSpeed")
+  self.save.options.speed = GameSpeed.cycle(self.save.options.speed, dir)
+  self:writeOptions()
+end
+
 function Game:keypressed(key)
   if self.stack and self.stack:top() and self.stack:top().onKeyPressed then
     self.stack:top():onKeyPressed(key)
@@ -546,6 +564,11 @@ function Game:keypressed(key)
   elseif key == "=" then
     self:zoomStep(1)
     return
+  elseif key == "1" then
+    -- cycle GAME SPEED (0.25X → 200X, logic only; audio unaffected);
+    -- R2/L2 on gamepad do the same (see gamepadpressed)
+    self:_cycleSpeed(1)
+    return
   elseif key == "2" then
     -- cycle COLORS (GBC / OG / OG INV / GBC INV / CLASSIC); the pack change
     -- forces Game.overworld:reloadMap, which rebuilds the live NPC array, so
@@ -626,6 +649,15 @@ function Game:gamepadpressed(joystick, button)
   -- a controller is being used: the touch overlay steps aside until the
   -- next screen touch (mobile only; a no-op elsewhere)
   TouchControls:noteGamepad()
+  -- shoulder buttons cycle GAME SPEED (R2/rightshoulder = faster,
+  -- L2/leftshoulder = slower; same as keyboard hotkey 1)
+  if button == "rightshoulder" then
+    self:_cycleSpeed(1)
+    return
+  elseif button == "leftshoulder" then
+    self:_cycleSpeed(-1)
+    return
+  end
   -- BindingsMenu's pad capture rides the same top-state routing as keys
   local top = self.stack and self.stack:top()
   if top and top.onGamepadPressed then

src/core/GameSpeed.lua

@@ -18,7 +18,7 @@ local GameSpeed = {}
 -- attempt is long enough that the iteration loop, not the engine, is the
 -- bottleneck. Vsync caps how much a real frame can do, so past 10X the
 -- multiplier is increasingly a ceiling rather than a rate.
-GameSpeed.LEVELS = { 1, 2, 4, 10, 20, 30, 50, 75, 100,200 }
+GameSpeed.LEVELS = { 1, 2, 3, 4, 10, 20, 30, 50, 75, 100, 200 }
 GameSpeed.DEFAULT = 1
 
 function GameSpeed.levelLabel(v)