Make the source pass the CI lint

The central pipeline lints where the old inline one did not, and it
aborts on any warning. Nothing here was actually wrong: 166 of the 243
warnings were the TIC-80 API and the game's own globals being undeclared,
which is what .luacheckrc is for — the same shape impostor already uses.

The rest was trailing whitespace on 14 lines, now stripped. INPUT_KEY_X
is unused but kept: it belongs to the LEFT/RIGHT/A/B/X/Y set and removing
it would leave a gap in the mapping, so luacheck is told to allow the
family.

Verified locally by merging the sources the way the pipeline does and
running luacheck over the result: 0 warnings, 0 errors.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

inc/window/window.configuration.lua

@@ -39,15 +39,15 @@ function ConfigurationWindow.draw()
   for i, control in ipairs(ConfigurationWindow.controls) do
     local current_y = y_start + (i - 1) * 12
     local color = Config.colors.green
-    
+
     if control.type == "numeric_stepper" then
       local value = control.get()
       local label_text = control.label
       local value_text = string.format(control.format, value)
-      
+
       -- Calculate x position for right-aligned value
       local value_x = x_value_right_align - (#value_text * char_width)
-      
+
       if i == ConfigurationWindow.selected_control then
         color = Config.colors.item
         Print.text("<", x_start -8, current_y, color)
@@ -70,7 +70,7 @@ function ConfigurationWindow.draw()
       end
     end
   end
-  
+
   Print.text("Press B to go back", x_start, 120, Config.colors.light_grey)
 end