feat(seed): curated FIFA17 dev content pack + opt-in game-scoped ownership seed

src/services/card_db.rs

@@ -38,6 +38,30 @@ impl CardDb {
         Ok(Self { cards })
     }
 
+    /// Merge a game's **opt-in development content pack** from
+    /// `{data_dir}/games/{game}/dev/cards.json` (a single `CardDefinition[]`).
+    /// This is NOT read by [`CardDb::load`]; it is loaded only when a game is
+    /// explicitly named in `Config::dev_content_games`, so default content stays
+    /// untouched. Returns the number of definitions merged. A missing file is an
+    /// error (opt-in means the pack is expected to exist).
+    pub fn load_game_dev(&mut self, data_dir: &str, game: &str) -> Result<usize> {
+        let path = Path::new(data_dir)
+            .join("games")
+            .join(game)
+            .join("dev")
+            .join("cards.json");
+        let content = std::fs::read_to_string(&path)
+            .with_context(|| format!("reading dev content pack {path:?}"))?;
+        let batch: Vec<CardDefinition> =
+            serde_json::from_str(&content).with_context(|| format!("parsing {path:?}"))?;
+        let n = batch.len();
+        for card in batch {
+            self.cards.insert(card.id.clone(), card);
+        }
+        tracing::info!("Loaded {} dev card definitions for game '{}'", n, game);
+        Ok(n)
+    }
+
     pub fn get(&self, id: &str) -> Option<&CardDefinition> {
         self.cards.get(id)
     }