feat: Phase 3 — polish & settings complete

Card pool:
- TOTW cards (5): overall 88-92, rarity "totw"
- Hero cards (5): overall 85-88, rarity "hero"
- Icon cards (5): overall 93-95, rarity "icon" (permanent, non-loan)

Packs:
- TOTW Pack (30,000 coins): 5 TOTW cards guaranteed
- Icon Pack (50,000 coins): 3 icon cards guaranteed
- Hero Pack (20,000 coins): 5 hero cards guaranteed

Objectives:
- Milestone objectives (6): win 10/50, score 100/500 goals, 10 SBCs, 25 packs

Formations:
- GET /formations returns 12 valid formation strings

Multiple named squads (#20):
- POST /squad with no squad_id always creates a new squad
- POST /squad with squad_id updates that specific squad
- GET /squads: list all squads for the club (metadata only)
- GET /squads/🆔 squad with players + chemistry
- DELETE /squads/🆔 remove a squad

Per-position goal stats (#41):
- Migration 0003: position_goals table
- POST /matches/result accepts optional goal_positions: ["ST","CAM",...]
- GET /statistics now includes position_goals map

Settings (#44-46):
- GET /settings: { difficulty, preferred_formation } with defaults
- PUT /settings: upsert any key-value combination

Draft mode skeleton (#38):
- GET /draft/squad?difficulty=... returns a randomly generated 11-player squad

Integration tests:
- 9 new tests covering: formations, pack buy/open, SBC submit, settings R/W,
  multiple squads, draft endpoint, goal position tracking, win streak

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

data/cards/hero_sample.json

@@ -0,0 +1,7 @@
+[
+  { "id": "card_hero_001", "name": "El Centrodelantero", "overall": 87, "position": "ST", "nation": "Spain", "league": "La Liga", "club": "Atletico Madrid", "pace": 84, "shooting": 88, "passing": 74, "dribbling": 83, "defending": 38, "physical": 80, "rarity": "hero", "image_path": null },
+  { "id": "card_hero_002", "name": "The Playmaker", "overall": 86, "position": "CAM", "nation": "Netherlands", "league": "Eredivisie", "club": "Ajax", "pace": 78, "shooting": 79, "passing": 90, "dribbling": 88, "defending": 50, "physical": 65, "rarity": "hero", "image_path": null },
+  { "id": "card_hero_003", "name": "Il Muro", "overall": 88, "position": "CB", "nation": "Italy", "league": "Serie A", "club": "Juventus", "pace": 80, "shooting": 42, "passing": 72, "dribbling": 70, "defending": 91, "physical": 90, "rarity": "hero", "image_path": null },
+  { "id": "card_hero_004", "name": "The Enforcer", "overall": 85, "position": "CDM", "nation": "Nigeria", "league": "Premier League", "club": "Chelsea", "pace": 76, "shooting": 60, "passing": 80, "dribbling": 75, "defending": 89, "physical": 88, "rarity": "hero", "image_path": null },
+  { "id": "card_hero_005", "name": "El Expreso", "overall": 87, "position": "LB", "nation": "Brazil", "league": "Brasileirao", "club": "Santos FC", "pace": 90, "shooting": 60, "passing": 82, "dribbling": 85, "defending": 88, "physical": 78, "rarity": "hero", "image_path": null }
+]