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/routes/division.rs

@@ -1,4 +1,5 @@
 use axum::{extract::State, Json};
+use rand::{Rng, SeedableRng};
 use serde_json::{json, Value};
 
 use crate::{
@@ -40,3 +41,93 @@ pub async fn get_division_history(State(state): State<AppState>) -> AppResult<Js
     let history = season_svc::get_history(&state.pool, &profile.id).await?;
     Ok(Json(json!({ "history": history, "total": history.len() })))
 }
+
+pub async fn get_division_leaderboard(State(state): State<AppState>) -> AppResult<Json<Value>> {
+    let profile = profile_svc::get_active_profile(&state.pool).await?;
+    let club = club_svc::get_club_by_profile(&state.pool, &profile.id).await?;
+    let season = season_svc::get_or_create(&state.pool, &profile.id).await?;
+
+    // Seed from division + season_number so the NPC table is stable within a season
+    let seed = (season.division as u64) * 1000 + season.season_number as u64;
+    let mut rng = rand::rngs::SmallRng::seed_from_u64(seed);
+
+    const NPC_NAMES: &[&str] = &[
+        "Riverside FC", "City Athletic", "County United", "Valley Rangers",
+        "Harbor Town FC", "Mountside City", "Lakewood Athletic", "Eastbrook United",
+        "Westfield Rovers", "Northgate FC", "Southport Athletic", "Ironbridge City",
+        "Milldale United", "Hillcrest Rangers", "Bayside FC", "Thornfield Athletic",
+        "Greenhill United", "Coldwater City", "Redbury Rangers", "Ashdown FC",
+    ];
+
+    // Pick 9 NPC names without repetition using the seeded RNG
+    let mut name_indices: Vec<usize> = (0..NPC_NAMES.len()).collect();
+    name_indices.sort_by_key(|&_i| rng.gen::<u64>());
+    let npc_names: Vec<&str> = name_indices[..9].iter().map(|&i| NPC_NAMES[i]).collect();
+
+    // Generate NPC records: clubs in top of table have more wins, bottom have more losses
+    let matches_played = season.matches_played;
+    let npc_matches = matches_played.max(1); // NPC clubs play same number of matches as player
+    let mut table: Vec<serde_json::Value> = npc_names
+        .iter()
+        .enumerate()
+        .map(|(idx, name)| {
+            // Quality bias: index 0-2 = stronger, 6-8 = weaker
+            let quality: f64 = 1.0 - (idx as f64 / 8.0); // 1.0 → 0.0
+            let expected_win_rate = 0.2 + quality * 0.6; // 0.2–0.8
+            let wins  = (npc_matches as f64 * expected_win_rate * (0.8 + rng.gen::<f64>() * 0.4)) as i64;
+            let losses = (npc_matches as f64 * (1.0 - expected_win_rate) * (0.8 + rng.gen::<f64>() * 0.4)) as i64;
+            let draws  = (npc_matches - wins - losses).max(0);
+            let pts    = wins * 3 + draws;
+            json!({
+                "club_name": name,
+                "wins": wins,
+                "draws": draws,
+                "losses": losses,
+                "pts": pts,
+                "matches_played": npc_matches,
+                "is_player": false,
+            })
+        })
+        .collect();
+
+    // Add player club row
+    let player_pts = season.wins * 3 + season.draws;
+    table.push(json!({
+        "club_name": club.name,
+        "wins": season.wins,
+        "draws": season.draws,
+        "losses": season.losses,
+        "pts": player_pts,
+        "matches_played": season.matches_played,
+        "is_player": true,
+    }));
+
+    // Sort by pts desc, then wins desc
+    table.sort_by(|a, b| {
+        let pts_a = a["pts"].as_i64().unwrap_or(0);
+        let pts_b = b["pts"].as_i64().unwrap_or(0);
+        pts_b.cmp(&pts_a).then_with(|| {
+            let w_b = b["wins"].as_i64().unwrap_or(0);
+            let w_a = a["wins"].as_i64().unwrap_or(0);
+            w_b.cmp(&w_a)
+        })
+    });
+
+    // Add position numbers
+    let table_with_pos: Vec<serde_json::Value> = table
+        .into_iter()
+        .enumerate()
+        .map(|(i, mut entry)| {
+            entry["position"] = json!(i as i64 + 1);
+            entry
+        })
+        .collect();
+
+    Ok(Json(json!({
+        "leaderboard": table_with_pos,
+        "division": season.division,
+        "season_number": season.season_number,
+        "promotion_threshold": 3,   // top 3 promote
+        "relegation_threshold": 8,  // bottom 2 relegate
+    })))
+}

src/routes/market.rs

@@ -12,6 +12,13 @@ use crate::{
     services::{club as club_svc, market as market_svc, profile as profile_svc},
 };
 
+pub async fn get_trade_history(State(state): State<AppState>) -> AppResult<Json<Value>> {
+    let profile = profile_svc::get_active_profile(&state.pool).await?;
+    let club = club_svc::get_club_by_profile(&state.pool, &profile.id).await?;
+    let trades = market_svc::get_trade_history(&state.pool, &club.id).await?;
+    Ok(Json(json!({ "trades": trades, "total": trades.len() })))
+}
+
 
 #[derive(Deserialize)]
 pub struct MarketQuery {
@@ -63,7 +70,7 @@ pub async fn post_market_sell(
     let profile = profile_svc::get_active_profile(&state.pool).await?;
     let club = club_svc::get_club_by_profile(&state.pool, &profile.id).await?;
 
-    let new_balance = market_svc::sell_card(&state.pool, &club.id, &req).await?;
+    let new_balance = market_svc::sell_card(&state.pool, &state.card_db, &club.id, &req).await?;
     Ok(Json(
         json!({ "new_coin_balance": new_balance, "message": "Card sold to NPC market" }),
     ))