Phase 25: division leaderboard, market trade history

- Market: record buy/sell history in market_history table; expose via
  GET /market/trade-history (last 30 events, newest first)
- Division: GET /division/leaderboard returns 10-club table with 9 seeded
  NPC entries + player row, sorted by pts; stable within a season
- rand feature small_rng enabled in Cargo.toml for SmallRng use
- 3 new integration tests (leaderboard count, sort order, empty trade history)
- Core: 96 tests passing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app.rs

@@ -190,6 +190,7 @@ 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/refresh", post(routes::market::post_market_refresh))
         .route("/market/my-listings", get(routes::market::get_my_listings))
         .route(
@@ -205,6 +206,7 @@ pub async fn build(pool: Pool, cfg: Config) -> Result<Router> {
         .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("/achievements", get(routes::achievements::get_achievements))
         .route("/notifications", get(routes::notifications::get_notifications))
         .route("/notifications/read-all", post(routes::notifications::mark_all_notifications_read))