feat: Phase 5 — events system complete

Adds a data-driven event system (#47 schema, #48 activation, #49 TOTW):

- EventDefinition JSON schema (event_type, effects, date range, is_manual)
- data/events/totw_week1.json — TOTW event active by date range (2024–2030),
  injects 5 TOTW cards into the market as [EVENT] listings
- data/events/seasonal_events.json — Spring Festival and Icon Weekend,
  manual-activation-only example events
- migrations/0004_events.sql — events override table (NULL/1/0 per event)
- services/event — load_event_definitions, compute_is_active (date range +
  manual override), get_active_events, get_all_with_status, activate/deactivate
- routes/events — GET /events, GET /events/:id, POST .../activate, .../deactivate
- services/market::refresh_npc_listings now accepts event_defs, injects bonus
  market cards from active events at 2× premium price
- 5 new integration tests (events list, single, activate/deactivate cycle,
  404 on unknown, market injection verification); 19/19 passing

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

tests/integration_test.rs

@@ -382,3 +382,103 @@ async fn test_win_streak_tracking() {
     assert_eq!(stats["win_streak"], 3);
     assert_eq!(stats["best_win_streak"], 3);
 }
+
+// ── Phase 5: Events ──────────────────────────────────────────────────────────
+
+#[tokio::test]
+async fn test_events_list() {
+    let app = build_test_app().await;
+    let (status, json) = json_get(&app, "/events").await;
+    assert_eq!(status, StatusCode::OK);
+    assert!(json["events"].is_array());
+    // TOTW Week 1 is date-range active (2024–2030)
+    let active = json["active_count"].as_u64().unwrap_or(0);
+    assert!(active >= 1, "expected at least 1 active event (totw_week1)");
+}
+
+#[tokio::test]
+async fn test_event_get_single() {
+    let app = build_test_app().await;
+    let (status, json) = json_get(&app, "/events/totw_week1").await;
+    assert_eq!(status, StatusCode::OK);
+    assert_eq!(json["event"]["id"], "totw_week1");
+    assert_eq!(json["is_active"], true);
+}
+
+#[tokio::test]
+async fn test_event_activate_deactivate() {
+    let app = build_test_app().await;
+
+    // spring_festival is manual-only — should start inactive
+    let (s, json) = json_get(&app, "/events/spring_festival").await;
+    assert_eq!(s, StatusCode::OK);
+    assert_eq!(json["is_active"], false);
+
+    // Activate it
+    let (s, json) = json_post(
+        &app,
+        "/events/spring_festival/activate",
+        serde_json::json!({}),
+    )
+    .await;
+    assert_eq!(s, StatusCode::OK);
+    assert_eq!(json["is_active"], true);
+
+    // Confirm it's now active
+    let (s, json) = json_get(&app, "/events/spring_festival").await;
+    assert_eq!(s, StatusCode::OK);
+    assert_eq!(json["is_active"], true);
+
+    // Deactivate it
+    let (s, json) = json_post(
+        &app,
+        "/events/spring_festival/deactivate",
+        serde_json::json!({}),
+    )
+    .await;
+    assert_eq!(s, StatusCode::OK);
+    assert_eq!(json["is_active"], false);
+
+    // Confirm inactive again
+    let (s, json) = json_get(&app, "/events/spring_festival").await;
+    assert_eq!(s, StatusCode::OK);
+    assert_eq!(json["is_active"], false);
+}
+
+#[tokio::test]
+async fn test_event_unknown_returns_404() {
+    let app = build_test_app().await;
+    let (status, _) = json_get(&app, "/events/no_such_event").await;
+    assert_eq!(status, StatusCode::NOT_FOUND);
+}
+
+#[tokio::test]
+async fn test_event_market_refresh_injects_totw_cards() {
+    let app = build_test_app().await;
+    auth(&app, "EventMarketPlayer").await;
+
+    // Trigger a market refresh (TOTW event is active by date range)
+    let (s, json) = json_post(&app, "/market/refresh", serde_json::json!({})).await;
+    assert_eq!(s, StatusCode::OK);
+    // totw_week1 has 5 bonus cards + up to 20 NPC listings
+    let count = json["listings_generated"].as_u64().unwrap_or(0);
+    assert!(
+        count >= 5,
+        "expected at least 5 listings (event bonus cards)"
+    );
+
+    // Check market contains at least one [EVENT] listing
+    let (s, market) = json_get(&app, "/market").await;
+    assert_eq!(s, StatusCode::OK);
+    let listings = market["listings"].as_array().expect("listings array");
+    let event_listing = listings.iter().any(|l| {
+        l["seller_name"]
+            .as_str()
+            .map(|n| n.starts_with("[EVENT]"))
+            .unwrap_or(false)
+    });
+    assert!(
+        event_listing,
+        "expected at least one [EVENT] market listing"
+    );
+}