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>

migrations/0006_seasons_loans_packs.sql

@@ -0,0 +1,19 @@
+-- Division / season tracking (one row per profile, reset each season)
+CREATE TABLE IF NOT EXISTS seasons (
+    profile_id TEXT PRIMARY KEY,
+    division INTEGER NOT NULL DEFAULT 5,
+    season_number INTEGER NOT NULL DEFAULT 1,
+    season_points INTEGER NOT NULL DEFAULT 0,
+    matches_played INTEGER NOT NULL DEFAULT 0,
+    wins INTEGER NOT NULL DEFAULT 0,
+    draws INTEGER NOT NULL DEFAULT 0,
+    losses INTEGER NOT NULL DEFAULT 0,
+    started_at TEXT NOT NULL
+);
+
+-- Pack open history: store which card_ids came out of each open
+ALTER TABLE packs ADD COLUMN opened_cards TEXT;
+ALTER TABLE packs ADD COLUMN opened_at TEXT;
+
+-- Club cosmetic customization
+ALTER TABLE clubs ADD COLUMN manager_name TEXT DEFAULT 'Player Manager';

migrations/0013_market_history.sql

@@ -0,0 +1,13 @@
+-- One row per buy or sell event, for trade history display
+CREATE TABLE IF NOT EXISTS market_history (
+    id          TEXT PRIMARY KEY,
+    club_id     TEXT NOT NULL,
+    card_id     TEXT NOT NULL,       -- definition card id
+    card_name   TEXT NOT NULL,
+    card_overall INTEGER NOT NULL,
+    trade_type  TEXT NOT NULL,       -- 'buy' | 'sell'
+    price       INTEGER NOT NULL,
+    traded_at   TEXT NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_market_history_club ON market_history (club_id, traded_at DESC);