Phase 11: FUT Champions mode and Division Rivals weekly rewards

FUT Champions (Weekend League):
- POST /fut-champs/start — open a new 30-match week (one active session at a time)
- GET /fut-champs — current session status with matches_remaining
- POST /fut-champs/:id/result — record a match; auto-completes and computes tier at 30
- POST /fut-champs/:id/claim — claim coins + pack reward (idempotent guard)
- GET /fut-champs/history — past sessions newest-first
- 11 reward tiers: Elite (27+ wins, 50k coins + icon pack) down to Bronze 1 (0 wins, 250 coins)

Division Rivals:
- POST /rivals/claim-weekly — claim weekly reward scaled by current division
- Week counter is monotonic (offline-safe, no real-time calendar dependency)
- Division 1-3 get a bonus pack alongside coins

Migration 0008 adds fut_champs_sessions table and two columns to seasons.
12 new integration tests — all 67 pass, clippy clean.

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

src/app.rs

@@ -194,6 +194,21 @@ 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("/notifications", get(routes::notifications::get_notifications))
+        .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/:session_id/result",
+            post(routes::fut_champs::post_champs_result),
+        )
+        .route(
+            "/fut-champs/:session_id/claim",
+            post(routes::fut_champs::post_claim_champs_rewards),
+        )
+        .route(
+            "/rivals/claim-weekly",
+            post(routes::fut_champs::post_claim_rivals_reward),
+        )
         .route("/draft/squad", get(routes::draft::get_draft_squad))
         .route("/draft/start", post(routes::draft::post_draft_start))
         .route("/draft/sessions/:id", get(routes::draft::get_draft_session))