Revert "feat(engine): bundle Rusty Pixel as a built-in theme"

This reverts commit 21ec03b157.

solitaire_engine/assets/themes/rusty-pixel/theme.ron

@@ -1,76 +0,0 @@
-// Rusty Pixel — pixel-art card theme generated via Claude Design.
-//
-// 53 PNGs at 256×384 (4× nearest-neighbor upscale of the source
-// 64×96 grid). Card aspect 2:3 matches the engine's layout
-// assumption. Drop this directory under
-// `<data_dir>/solitaire_quest/themes/rusty-pixel/` and the theme
-// registry picks it up at next launch.
-(
-    meta: (
-        id: "rusty-pixel",
-        name: "Rusty Pixel",
-        author: "Claude Design",
-        version: "0.1.0",
-        card_aspect: (2, 3),
-        // Opt in to nearest-neighbor sampling so the pixel grid stays
-        // crisp at non-integer scales (Bevy's default bilinear filter
-        // mushes 256x384 pixel art when displayed at ~150x200 on a
-        // typical desktop window).
-        pixel_art: true,
-    ),
-    back: "back.png",
-    faces: {
-        "clubs_ace":      "clubs_ace.png",
-        "clubs_2":        "clubs_2.png",
-        "clubs_3":        "clubs_3.png",
-        "clubs_4":        "clubs_4.png",
-        "clubs_5":        "clubs_5.png",
-        "clubs_6":        "clubs_6.png",
-        "clubs_7":        "clubs_7.png",
-        "clubs_8":        "clubs_8.png",
-        "clubs_9":        "clubs_9.png",
-        "clubs_10":       "clubs_10.png",
-        "clubs_jack":     "clubs_jack.png",
-        "clubs_queen":    "clubs_queen.png",
-        "clubs_king":     "clubs_king.png",
-        "diamonds_ace":   "diamonds_ace.png",
-        "diamonds_2":     "diamonds_2.png",
-        "diamonds_3":     "diamonds_3.png",
-        "diamonds_4":     "diamonds_4.png",
-        "diamonds_5":     "diamonds_5.png",
-        "diamonds_6":     "diamonds_6.png",
-        "diamonds_7":     "diamonds_7.png",
-        "diamonds_8":     "diamonds_8.png",
-        "diamonds_9":     "diamonds_9.png",
-        "diamonds_10":    "diamonds_10.png",
-        "diamonds_jack":  "diamonds_jack.png",
-        "diamonds_queen": "diamonds_queen.png",
-        "diamonds_king":  "diamonds_king.png",
-        "hearts_ace":     "hearts_ace.png",
-        "hearts_2":       "hearts_2.png",
-        "hearts_3":       "hearts_3.png",
-        "hearts_4":       "hearts_4.png",
-        "hearts_5":       "hearts_5.png",
-        "hearts_6":       "hearts_6.png",
-        "hearts_7":       "hearts_7.png",
-        "hearts_8":       "hearts_8.png",
-        "hearts_9":       "hearts_9.png",
-        "hearts_10":      "hearts_10.png",
-        "hearts_jack":    "hearts_jack.png",
-        "hearts_queen":   "hearts_queen.png",
-        "hearts_king":    "hearts_king.png",
-        "spades_ace":     "spades_ace.png",
-        "spades_2":       "spades_2.png",
-        "spades_3":       "spades_3.png",
-        "spades_4":       "spades_4.png",
-        "spades_5":       "spades_5.png",
-        "spades_6":       "spades_6.png",
-        "spades_7":       "spades_7.png",
-        "spades_8":       "spades_8.png",
-        "spades_9":       "spades_9.png",
-        "spades_10":      "spades_10.png",
-        "spades_jack":    "spades_jack.png",
-        "spades_queen":   "spades_queen.png",
-        "spades_king":    "spades_king.png",
-    },
-)