Add justfile, ols/odinfmt config, tests and Gitea workflows; drop odin.json

- justfile with build/run/check/test/release/package/fmt/clean recipes
- ols.json and odinfmt.json for neovim (ols)
- Tests for memory game rules and card animation; memory.deal and
  memory.select_card split out so logic is testable without a window
- Gitea workflows: build+test on main/develop, package and upload to the
  generic package registry on version branches
- Game changes to the executable's directory so packaged builds find assets

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

src/memory/memory.odin

@@ -51,7 +51,14 @@ resolve_timer: f32
 win_t: f32 // fades in the win panel
 restart_requested: bool
 
+// Deals a new game and renders the card faces. Needs the window to exist.
 start :: proc(game_theme: themes.Theme) {
+    deal(game_theme)
+    for &c in cards { card.build_face(&c, theme) }
+}
+
+// Shuffles, lays out and resets the game state without touching the GPU
+deal :: proc(game_theme: themes.Theme) {
     theme = game_theme
 
     deck := HIRAGANA
@@ -75,7 +82,6 @@ start :: proc(game_theme: themes.Theme) {
             themes.CARD_WIDTH,
             themes.CARD_HEIGHT,
         }
-        card.build_face(&c, theme)
     }
 
     state = .WAITING
@@ -93,14 +99,14 @@ unload :: proc() {
     for &c in cards { card.unload_face(&c) }
 }
 
-@(private)
 can_pick :: proc(i: int) -> bool {
     c := &cards[i]
     return (state == .WAITING || state == .FIRST) && !c.face_up && !c.matched
 }
 
-@(private)
-pick :: proc(i: int) {
+// Turns card i face up if it can be picked. Returns false when the pick is not allowed.
+select_card :: proc(i: int) -> bool {
+    if !can_pick(i) { return false }
     cards[i].face_up = true
     audio.play(.FLIP)
     if state == .WAITING {
@@ -113,6 +119,7 @@ pick :: proc(i: int) {
         resolve_timer = is_match ? MATCH_DELAY : MISMATCH_DELAY
         state = .RESOLVING
     }
+    return true
 }
 
 @(private)
@@ -155,8 +162,7 @@ update :: proc(dt: f32) {
         elapsed += dt
         if raylib.IsMouseButtonPressed(.LEFT) {
             for &c, i in cards {
-                if can_pick(i) && card.is_hovered(&c) {
-                    pick(i)
+                if card.is_hovered(&c) && select_card(i) {
                     break
                 }
             }