Add Katakana, Korean and Thai games and difficulty levels

- decks package: Hiragana, Katakana, Hangul jamo and Thai consonants
  (Thai readings carry the letter's name word, since sounds repeat)
- Per-script fonts: Jua for Hangul, Mali for Thai (both OFL)
- Memory game works with any deck; Easy 3x4, Normal 4x6, Hard 4x8
- Language menus pick a deck and difficulty, with number/arrow key shortcuts
- Tests cover every deck, difficulty, and font glyph coverage

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/ui/ui.odin

@@ -5,6 +5,8 @@ import assets "../assets"
 import audio "../audio"
 import themes "../themes"
 
+Font_Style :: assets.Font_Style
+
 TEXT_SPACING :: 1
 
 @(private)
@@ -25,38 +27,42 @@ set_hovered :: proc() {
     any_hovered = true
 }
 
-measure_text :: proc(text: cstring, size: f32, bold := false) -> raylib.Vector2 {
-    return raylib.MeasureTextEx(assets.get_font(bold), text, size, TEXT_SPACING)
+measure_text :: proc(text: cstring, size: f32, style: Font_Style = .REGULAR) -> raylib.Vector2 {
+    return raylib.MeasureTextEx(assets.get_font(style), text, size, TEXT_SPACING)
 }
 
-draw_text :: proc(text: cstring, pos: raylib.Vector2, size: f32, color: raylib.Color, bold := false) {
-    raylib.DrawTextEx(assets.get_font(bold), text, pos, size, TEXT_SPACING, color)
+draw_text :: proc(text: cstring, pos: raylib.Vector2, size: f32, color: raylib.Color, style: Font_Style = .REGULAR) {
+    raylib.DrawTextEx(assets.get_font(style), text, pos, size, TEXT_SPACING, color)
 }
 
 // Draws text horizontally centered on center_x with its top at y
-draw_text_centered :: proc(text: cstring, center_x, y, size: f32, color: raylib.Color, bold := false, shadow := false) {
-    w := measure_text(text, size, bold).x
+draw_text_centered :: proc(text: cstring, center_x, y, size: f32, color: raylib.Color,
+                           style: Font_Style = .REGULAR, shadow := false) {
+    w := measure_text(text, size, style).x
     pos := raylib.Vector2{center_x - w / 2, y}
     if shadow {
-        draw_text(text, pos + {0, size * 0.05}, size, raylib.Fade(themes.BLACK, 0.18), bold)
+        draw_text(text, pos + {0, size * 0.05}, size, raylib.Fade(themes.BLACK, 0.18), style)
     }
-    draw_text(text, pos, size, color, bold)
+    draw_text(text, pos, size, color, style)
 }
 
 // Draws text centered in a rectangle
-draw_text_in_rect :: proc(text: cstring, rect: raylib.Rectangle, size: f32, color: raylib.Color, bold := false) {
-    dims := measure_text(text, size, bold)
+draw_text_in_rect :: proc(text: cstring, rect: raylib.Rectangle, size: f32, color: raylib.Color,
+                          style: Font_Style = .REGULAR) {
+    dims := measure_text(text, size, style)
     pos := raylib.Vector2{rect.x + (rect.width - dims.x) / 2, rect.y + (rect.height - dims.y) / 2}
-    draw_text(text, pos, size, color, bold)
+    draw_text(text, pos, size, color, style)
 }
 
 draw_title :: proc(text: cstring, y: f32, color: raylib.Color, size: f32 = themes.TITLE_FONT_SIZE) {
-    draw_text_centered(text, themes.SCREEN_WIDTH / 2, y, size, color, bold = true, shadow = true)
+    draw_text_centered(text, themes.SCREEN_WIDTH / 2, y, size, color, style = .BOLD, shadow = true)
 }
 
-// A rounded button with hover, press and shadow states. Returns true when clicked.
+// A rounded button with hover, press and shadow states. Returns true when clicked
+// or when its hotkey is pressed.
 button :: proc(rect: raylib.Rectangle, text: cstring, color: raylib.Color,
-               text_color := themes.WHITE, font_size: f32 = themes.BUTTON_FONT_SIZE) -> bool {
+               text_color := themes.WHITE, font_size: f32 = themes.BUTTON_FONT_SIZE,
+               hotkey := raylib.KeyboardKey.KEY_NULL, selected := false) -> bool {
     hovered := raylib.CheckCollisionPointRec(raylib.GetMousePosition(), rect)
     pressed := hovered && raylib.IsMouseButtonDown(.LEFT)
     if hovered { set_hovered() }
@@ -76,9 +82,14 @@ button :: proc(rect: raylib.Rectangle, text: cstring, color: raylib.Color,
     raylib.DrawRectangleRounded(shadow, 0.4, 12, raylib.Fade(themes.BLACK, 0.18))
     body := raylib.Rectangle{rect.x, rect.y - lift, rect.width, rect.height}
     raylib.DrawRectangleRounded(body, 0.4, 12, fill)
-    draw_text_in_rect(text, body, font_size, text_color, bold = true)
+    if selected {
+        ring := raylib.Rectangle{body.x - 4, body.y - 4, body.width + 8, body.height + 8}
+        raylib.DrawRectangleRoundedLinesEx(ring, 0.4, 12, 3, color)
+    }
+    draw_text_in_rect(text, body, font_size, text_color, style = .BOLD)
 
     clicked := hovered && raylib.IsMouseButtonPressed(.LEFT)
+    if hotkey != .KEY_NULL && raylib.IsKeyPressed(hotkey) { clicked = true }
     if clicked { audio.play(.CLICK) }
     return clicked
 }