feat: Phase 2 — game feel complete

Chemistry & squads:
- Chemistry calculation on GET /squad (club/league/nation links, max 100)
- Formation validation on POST /squad (exactly 11 starters, exactly 1 GK)

Objectives:
- Weekly objectives JSON (4 objectives: warrior, goals, dedicated, SBC)
- Daily objectives auto-reset at midnight UTC (background task)

SBC validation expanded:
- max_overall per-player enforcement
- required_clubs validation
- min_players_from_same_nation validation
- min_players_from_same_club validation

Market:
- GET /market?min_overall=X&position=Y filtering
- Expiry cleanup runs before every NPC refresh
- NPC market auto-refresh every 24h (background task, runs at startup)

Matches:
- GET /matches/opponent?difficulty=beginner|professional|world_class|legendary
  generates a random AI opponent squad from the card pool

Statistics:
- win_streak and best_win_streak tracking (migration 0002)
- GET /statistics/history?limit=N — last N matches with summary stats

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

src/routes/market.rs

@@ -1,4 +1,8 @@
-use axum::{extract::State, Json};
+use axum::{
+    extract::{Query, State},
+    Json,
+};
+use serde::Deserialize;
 use serde_json::{json, Value};
 
 use crate::{
@@ -8,8 +12,31 @@ use crate::{
     services::{club as club_svc, market as market_svc, profile as profile_svc},
 };
 
-pub async fn get_market(State(state): State<AppState>) -> AppResult<Json<Value>> {
-    let listings = market_svc::get_active_listings(&state.pool, &state.card_db).await?;
+#[derive(Deserialize)]
+pub struct MarketQuery {
+    pub min_overall: Option<u8>,
+    pub position: Option<String>,
+}
+
+pub async fn get_market(
+    State(state): State<AppState>,
+    Query(query): Query<MarketQuery>,
+) -> AppResult<Json<Value>> {
+    let all = market_svc::get_active_listings(&state.pool, &state.card_db).await?;
+    let listings: Vec<_> = all
+        .into_iter()
+        .filter(|l| {
+            query
+                .min_overall
+                .map(|min| l.card.overall >= min)
+                .unwrap_or(true)
+                && query
+                    .position
+                    .as_ref()
+                    .map(|p| l.card.position.eq_ignore_ascii_case(p))
+                    .unwrap_or(true)
+        })
+        .collect();
     Ok(Json(
         json!({ "listings": listings, "total": listings.len() }),
     ))