feat(content): production content-pack loader + referenced-definition preflight

Production real-profile content is loaded via an explicit path, NOT the dev-only
OPENFUT_DEV_CONTENT_GAMES gate:
- Config.content_packs from env OPENFUT_CONTENT_PACKS (comma-sep file paths).
- CardDb::load_pack(path): merge an explicit CardDefinition[] production pack.
- app::build loads dev packs then production packs.

Preflight (app::build, always on): every owned_cards.card_id MUST resolve to a
loaded CardDefinition. A real profile with owned players but even ONE missing
definition fails LOUDLY instead of silently serving an empty /collection; an
empty owned_cards table (fresh DB / tests) passes.

2 preflight integration tests (missing def fails, loaded def passes). clippy
-D warnings clean; full suite 151 tests green.

src/app.rs

@@ -46,7 +46,34 @@ pub async fn build(pool: Pool, cfg: Config) -> Result<Router> {
     for game in &cfg.dev_content_games {
         card_db.load_game_dev(&cfg.data_dir, game)?;
     }
+    for pack in &cfg.content_packs {
+        card_db.load_pack(pack)?;
+    }
     let card_db = Arc::new(card_db);
+
+    // Content preflight: every owned card MUST reference a loaded CardDefinition.
+    // A real profile with owned players but missing definitions fails LOUDLY here
+    // rather than silently serving an empty /collection. Empty owned_cards (fresh
+    // DB, tests) passes. A SINGLE missing definition is caught, not only the
+    // zero-loaded case.
+    {
+        let referenced: Vec<String> =
+            sqlx::query_scalar("SELECT DISTINCT card_id FROM owned_cards")
+                .fetch_all(&pool)
+                .await?;
+        let missing: Vec<String> = referenced
+            .into_iter()
+            .filter(|id| card_db.get(id).is_none())
+            .collect();
+        if !missing.is_empty() {
+            let sample: Vec<&String> = missing.iter().take(5).collect();
+            anyhow::bail!(
+                "content preflight failed: {} owned card(s) reference CardDefinitionId(s) not loaded (e.g. {:?}). Load the production content pack via OPENFUT_CONTENT_PACKS.",
+                missing.len(),
+                sample
+            );
+        }
+    }
     let pack_defs = Arc::new(load_pack_definitions(&cfg.data_dir)?);
     let obj_defs = Arc::new(load_objective_definitions(&cfg.data_dir)?);
     let sbc_defs = Arc::new(load_sbc_definitions(&cfg.data_dir)?);
@@ -178,7 +205,10 @@ pub async fn build(pool: Pool, cfg: Config) -> Result<Router> {
         .route("/squads/:squad_id", get(routes::squad::get_squad_by_id))
         .route("/squads/:squad_id", delete(routes::squad::delete_squad))
         .route("/objectives", get(routes::objectives::get_objectives))
-        .route("/objectives/:objective_id", get(routes::objectives::get_objective))
+        .route(
+            "/objectives/:objective_id",
+            get(routes::objectives::get_objective),
+        )
         .route(
             "/objectives/claim",
             post(routes::objectives::post_claim_objective),
@@ -196,7 +226,10 @@ pub async fn build(pool: Pool, cfg: Config) -> Result<Router> {
         .route("/market", get(routes::market::get_market))
         .route("/market/buy", post(routes::market::post_market_buy))
         .route("/market/sell", post(routes::market::post_market_sell))
-        .route("/market/trade-history", get(routes::market::get_trade_history))
+        .route(
+            "/market/trade-history",
+            get(routes::market::get_trade_history),
+        )
         .route("/market/refresh", post(routes::market::post_market_refresh))
         .route("/market/my-listings", get(routes::market::get_my_listings))
         .route(
@@ -211,15 +244,36 @@ pub async fn build(pool: Pool, cfg: Config) -> Result<Router> {
         .route("/settings", get(routes::settings::get_settings))
         .route("/settings", put(routes::settings::put_settings))
         .route("/division", get(routes::division::get_division))
-        .route("/division/history", get(routes::division::get_division_history))
-        .route("/division/leaderboard", get(routes::division::get_division_leaderboard))
+        .route(
+            "/division/history",
+            get(routes::division::get_division_history),
+        )
+        .route(
+            "/division/leaderboard",
+            get(routes::division::get_division_leaderboard),
+        )
         .route("/achievements", get(routes::achievements::get_achievements))
-        .route("/notifications", get(routes::notifications::get_notifications))
-        .route("/notifications/read-all", post(routes::notifications::mark_all_notifications_read))
-        .route("/notifications/:id/read", patch(routes::notifications::mark_notification_read))
+        .route(
+            "/notifications",
+            get(routes::notifications::get_notifications),
+        )
+        .route(
+            "/notifications/read-all",
+            post(routes::notifications::mark_all_notifications_read),
+        )
+        .route(
+            "/notifications/:id/read",
+            patch(routes::notifications::mark_notification_read),
+        )
         .route("/fut-champs", get(routes::fut_champs::get_fut_champs))
-        .route("/fut-champs/start", post(routes::fut_champs::post_start_fut_champs))
-        .route("/fut-champs/history", get(routes::fut_champs::get_champs_history))
+        .route(
+            "/fut-champs/start",
+            post(routes::fut_champs::post_start_fut_champs),
+        )
+        .route(
+            "/fut-champs/history",
+            get(routes::fut_champs::get_champs_history),
+        )
         .route(
             "/fut-champs/:session_id/result",
             post(routes::fut_champs::post_champs_result),