Refactor(English): Rename all files and identifiers from Dutch to English

Renamed files: constanten→constants, adt-positie→adt-position,
adt-doolhof→adt-maze, adt-sleutel→adt-key, adt-tijdslimiet→adt-timer,
adt-teken→adt-draw, adt-spel→adt-game. All message names, variables,
comments, and tests converted to English.

Also fixed counter location bug (time-label x/y were swapped).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pacman-project/constants.rkt

@@ -0,0 +1,134 @@
+#lang r7rs
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;                                Constants                                  ;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+;; All configuration constants for the Pac-Man game. Prevents magic numbers
+;; throughout the codebase and makes the game easily configurable.
+
+(define-library (pacman-project constants)
+  (import (scheme base))
+  (export ;; Window
+          window-width-px
+          window-height-px
+
+          ;; Maze grid
+          cell-size-px
+          maze-offset-y
+          maze-wall-shrink
+
+          ;; Cell types
+          cell-type-coin
+          cell-type-wall
+          cell-type-empty
+          cell-type-key
+          cell-type-door
+
+          ;; Coin rendering
+          coin-inset
+
+          ;; Sprites
+          sprite-scale-pacman
+          sprite-scale-key
+          sprite-scale-key-ui
+
+          ;; Animation
+          animation-interval-ms
+
+          ;; Score
+          points-per-coin
+
+          ;; Time limit
+          start-time-seconds
+          ms-per-second
+          time-bonus-per-coin
+
+          ;; Key placement
+          max-placement-attempts
+
+          ;; Rotation angles
+          rotation-right
+          rotation-left
+          rotation-up
+          rotation-down
+
+          ;; UI positions
+          score-text-size
+          score-text-x
+          score-text-y
+          time-text-size
+          time-label-x
+          time-label-y
+          time-value-x
+          time-value-y
+          separator-x
+          separator-width
+          key-ui-x
+          key-ui-y)
+
+  (begin
+
+    ;; Window dimensions
+    (define window-width-px 1000)
+    (define window-height-px 830)
+
+    ;; Maze grid configuration
+    (define cell-size-px 24)
+    (define maze-offset-y 97)
+    (define maze-wall-shrink 6)
+
+    ;; Cell type encoding for the maze grid
+    (define cell-type-coin 0)
+    (define cell-type-wall 1)
+    (define cell-type-empty 2)
+    (define cell-type-key 3)
+    (define cell-type-door 4)
+
+    ;; Coin rendering: inset in pixels from cell edge
+    (define coin-inset 7)
+
+    ;; Sprite scale factors
+    (define sprite-scale-pacman 1.5)
+    (define sprite-scale-key 1.5)
+    (define sprite-scale-key-ui 3)
+
+    ;; Animation timing
+    (define animation-interval-ms 100)
+
+    ;; Score configuration
+    (define points-per-coin 10)
+
+    ;; Time limit configuration
+    (define start-time-seconds 60)
+    (define ms-per-second 1000)
+    (define time-bonus-per-coin 1)
+
+    ;; Key placement
+    (define max-placement-attempts 1000)
+
+    ;; Rotation angles (degrees)
+    (define rotation-right 0)
+    (define rotation-left 180)
+    (define rotation-up 90)
+    (define rotation-down -90)
+
+    ;; UI positions for score display
+    (define score-text-size 40)
+    (define score-text-x 560)
+    (define score-text-y 20)
+
+    ;; UI positions for time display (right side of separator)
+    (define time-text-size 35)
+    (define time-label-x 710)
+    (define time-label-y 300)
+    (define time-value-x 800)
+    (define time-value-y 400)
+
+    ;; Separator line between play field and UI
+    (define separator-x 670)
+    (define separator-width 24)
+
+    ;; Key UI position (next to score)
+    (define key-ui-x 20)
+    (define key-ui-y 35)))