Save best scores and last difficulty to a JSON profile

- profile package: best moves, best time and games played per
  deck/difficulty, stored in the user data folder
- Win panel shows the best (or New best!), language menu shows bests
- Profile memory always comes from the heap allocator (it outlives callers)

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

main.odin

@@ -1,11 +1,14 @@
 package main
 
+import "core:fmt"
+import "core:reflect"
 import raylib "vendor:raylib"
 import assets "src/assets"
 import audio "src/audio"
 import card "src/card"
 import decks "src/decks"
 import memory "src/memory"
+import profile "src/profile"
 import screens "src/screens"
 import themes "src/themes"
 import ui "src/ui"
@@ -40,9 +43,16 @@ main :: proc() {
     defer card.unload_art()
     defer memory.unload()
 
+    if !profile.init() {
+        raylib.TraceLog(.WARNING, "PROFILE: Could not read saved scores, starting fresh")
+    }
+
     screen := themes.Screen.MAIN_MENU
     language := decks.Language.JAPANESE
     difficulty := memory.Difficulty.NORMAL
+    if saved, ok := reflect.enum_from_name(memory.Difficulty, profile.data.difficulty); ok {
+        difficulty = saved
+    }
     running := true
     for running && !raylib.WindowShouldClose() {
         dt := raylib.GetFrameTime()
@@ -82,6 +92,8 @@ main :: proc() {
         }
         ui.end_frame()
         raylib.EndDrawing()
+        free_all(context.temp_allocator)
+        profile.set_difficulty(fmt.tprintf("%v", difficulty))
 
         // Building card faces renders into textures, so do it outside of drawing
         if deck, ok := start_deck.?; ok {