Initial commit: OpenFUT Core

Offline Ultimate Team backend — game-independent REST API.

- 19 API endpoints: auth, profiles, clubs, cards, packs, squads,
  objectives, SBCs, match rewards, NPC market, statistics
- Axum + SQLite + SQLx with full migrations
- Weighted pack generator, SBC validation engine
- JSON-driven mod data (cards, packs, objectives, SBCs)
- 5 integration tests passing

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

data/sbcs/starter_sbcs.json

@@ -0,0 +1,50 @@
+[
+  {
+    "id": "sbc_bronze_upgrade",
+    "name": "Bronze Upgrade",
+    "description": "Submit 11 bronze players for a silver pack.",
+    "requirements": {
+      "squad_size": 11,
+      "min_overall": null,
+      "max_overall": 64,
+      "min_chemistry": null,
+      "required_leagues": [],
+      "required_nations": [],
+      "required_clubs": [],
+      "min_players_from_same_league": null,
+      "min_players_from_same_nation": null,
+      "min_players_from_same_club": null
+    },
+    "reward": {
+      "coins": 0,
+      "xp": 200,
+      "pack_id": "silver_pack"
+    },
+    "expires_at": null,
+    "repeatable": true
+  },
+  {
+    "id": "sbc_hybrid_nations",
+    "name": "Hybrid Nations",
+    "description": "Build a squad of 11 players with at least one Brazilian and one Argentinian.",
+    "requirements": {
+      "squad_size": 11,
+      "min_overall": 70,
+      "max_overall": null,
+      "min_chemistry": null,
+      "required_leagues": [],
+      "required_nations": ["Brazil", "Argentina"],
+      "required_clubs": [],
+      "min_players_from_same_league": null,
+      "min_players_from_same_nation": null,
+      "min_players_from_same_club": null
+    },
+    "reward": {
+      "coins": 2000,
+      "xp": 400,
+      "pack_id": "gold_pack"
+    },
+    "expires_at": null,
+    "repeatable": false
+  }
+]