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/card/card.odin

@@ -2,6 +2,7 @@ package card
 
 import "core:math"
 import raylib "vendor:raylib"
+import assets "../assets"
 import themes "../themes"
 import ui "../ui"
 
@@ -19,8 +20,9 @@ HOVER_LIFT     :: 4
 
 Card :: struct {
     rect:     raylib.Rectangle, // resting position on screen
-    text:     cstring,
-    is_kana:  bool,
+    text:      cstring,
+    hint:      cstring, // small second line on reading cards
+    is_symbol: bool,    // script symbol (vs. its reading)
     pair_id:  int,
     face_up:  bool, // logical state; the animation follows it
     matched:  bool,
@@ -154,21 +156,34 @@ get_back_art :: proc(flag: themes.Flag) -> raylib.Texture2D {
     return back_art[flag].texture
 }
 
-// Renders the card's face into its own texture
-build_face :: proc(card: ^Card, theme: themes.Theme) {
+// Font size that fits text inside the card width
+@(private)
+fit_size :: proc(text: cstring, size: f32, style: assets.Font_Style) -> f32 {
+    max_width: f32 = ART_WIDTH * 0.78
+    width := ui.measure_text(text, size, style).x
+    return width > max_width ? size * max_width / width : size
+}
+
+// Renders the card's face into its own texture. Symbols use their script's font.
+build_face :: proc(card: ^Card, theme: themes.Theme, symbol_style: assets.Font_Style) {
     unload_face(card)
     card.face_art = new_art_texture(theme.primary)
     raylib.BeginTextureMode(card.face_art)
     draw_frame(theme.card_face, theme.primary)
     raylib.DrawRectangleRoundedLinesEx(art_rect(16), ROUNDNESS, SEGMENTS, 2, raylib.Fade(theme.primary, 0.35))
 
-    size: f32 = card.is_kana ? 132 : 96
-    color := card.is_kana ? theme.ink : theme.primary
-    // Shrink long romaji (e.g. "TSU") to fit inside the card
-    max_width: f32 = ART_WIDTH * 0.78
-    width := ui.measure_text(card.text, size, bold = true).x
-    if width > max_width { size *= max_width / width }
-    ui.draw_text_in_rect(card.text, art_rect(), size, color, bold = true)
+    if card.is_symbol {
+        ui.draw_text_in_rect(card.text, art_rect(), fit_size(card.text, 132, symbol_style), theme.ink, symbol_style)
+    } else if card.hint == nil {
+        ui.draw_text_in_rect(card.text, art_rect(), fit_size(card.text, 96, .BOLD), theme.primary, .BOLD)
+    } else {
+        // Reading on top, hint underneath
+        main_rect := art_rect()
+        main_rect.height -= 56
+        ui.draw_text_in_rect(card.text, main_rect, fit_size(card.text, 88, .BOLD), theme.primary, .BOLD)
+        hint_rect := raylib.Rectangle{0, ART_HEIGHT * 0.62, ART_WIDTH, 60}
+        ui.draw_text_in_rect(card.hint, hint_rect, fit_size(card.hint, 34, .REGULAR), theme.ink, .REGULAR)
+    }
     raylib.EndTextureMode()
 }