Phase 7 (Core): chemistry v2, expanded card pool & search filters

- Chemistry v2: FUT-style link scoring with per-player breakdown
  (club +3/link cap 6, league +1/link cap 4, nation +1/link cap 3;
   player cap 10, team cap 100); chemistry response now includes
   per-player breakdown with club/league/nation link counts and pts
- Card pool: 34 new cards across Premier League, La Liga, Bundesliga
  with overlapping clubs/nations for meaningful chemistry testing
- Card search: extended GET /cards with nation, league, club,
  min_overall, max_overall, limit query params; results sorted by
  overall descending
- Match opponent: added "ultimate" difficulty band (85+ OVR);
  random formation selection from 6 tactical formations; falls back
  to lower OVR pool when not enough cards at the requested band
- Tests: 9 new integration tests (28 total, all passing)

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

data/cards/bundesliga.json

@@ -0,0 +1,172 @@
+[
+  {
+    "id": "card_bl_001",
+    "name": "Klaus Berger",
+    "overall": 84,
+    "position": "ST",
+    "nation": "Germany",
+    "league": "Bundesliga",
+    "club": "Röder FC",
+    "pace": 82,
+    "shooting": 87,
+    "passing": 72,
+    "dribbling": 80,
+    "defending": 36,
+    "physical": 84,
+    "rarity": "gold",
+    "image_path": null
+  },
+  {
+    "id": "card_bl_002",
+    "name": "Felix Hartmann",
+    "overall": 83,
+    "position": "CM",
+    "nation": "Germany",
+    "league": "Bundesliga",
+    "club": "Röder FC",
+    "pace": 74,
+    "shooting": 74,
+    "passing": 86,
+    "dribbling": 80,
+    "defending": 72,
+    "physical": 76,
+    "rarity": "gold",
+    "image_path": null
+  },
+  {
+    "id": "card_bl_003",
+    "name": "Matteo Ricci",
+    "overall": 82,
+    "position": "CAM",
+    "nation": "Italy",
+    "league": "Bundesliga",
+    "club": "Röder FC",
+    "pace": 76,
+    "shooting": 80,
+    "passing": 85,
+    "dribbling": 84,
+    "defending": 42,
+    "physical": 66,
+    "rarity": "gold",
+    "image_path": null
+  },
+  {
+    "id": "card_bl_004",
+    "name": "Jan Schreiber",
+    "overall": 81,
+    "position": "CB",
+    "nation": "Germany",
+    "league": "Bundesliga",
+    "club": "Röder FC",
+    "pace": 74,
+    "shooting": 40,
+    "passing": 66,
+    "dribbling": 56,
+    "defending": 85,
+    "physical": 87,
+    "rarity": "gold",
+    "image_path": null
+  },
+  {
+    "id": "card_bl_005",
+    "name": "Lucas Fonseca",
+    "overall": 83,
+    "position": "LW",
+    "nation": "Brazil",
+    "league": "Bundesliga",
+    "club": "Blau Stern München",
+    "pace": 90,
+    "shooting": 78,
+    "passing": 77,
+    "dribbling": 88,
+    "defending": 32,
+    "physical": 66,
+    "rarity": "gold",
+    "image_path": null
+  },
+  {
+    "id": "card_bl_006",
+    "name": "Stefan Wolf",
+    "overall": 82,
+    "position": "CDM",
+    "nation": "Germany",
+    "league": "Bundesliga",
+    "club": "Blau Stern München",
+    "pace": 72,
+    "shooting": 64,
+    "passing": 78,
+    "dribbling": 74,
+    "defending": 85,
+    "physical": 82,
+    "rarity": "gold",
+    "image_path": null
+  },
+  {
+    "id": "card_bl_007",
+    "name": "Marco Bauer",
+    "overall": 80,
+    "position": "RB",
+    "nation": "Germany",
+    "league": "Bundesliga",
+    "club": "Blau Stern München",
+    "pace": 82,
+    "shooting": 54,
+    "passing": 74,
+    "dribbling": 74,
+    "defending": 80,
+    "physical": 76,
+    "rarity": "gold",
+    "image_path": null
+  },
+  {
+    "id": "card_bl_008",
+    "name": "Henri Delacroix",
+    "overall": 84,
+    "position": "ST",
+    "nation": "France",
+    "league": "Bundesliga",
+    "club": "Rhein United",
+    "pace": 86,
+    "shooting": 87,
+    "passing": 73,
+    "dribbling": 82,
+    "defending": 38,
+    "physical": 80,
+    "rarity": "gold",
+    "image_path": null
+  },
+  {
+    "id": "card_bl_009",
+    "name": "Tobias Kohl",
+    "overall": 80,
+    "position": "GK",
+    "nation": "Germany",
+    "league": "Bundesliga",
+    "club": "Rhein United",
+    "pace": 56,
+    "shooting": 16,
+    "passing": 60,
+    "dribbling": 30,
+    "defending": 82,
+    "physical": 82,
+    "rarity": "gold",
+    "image_path": null
+  },
+  {
+    "id": "card_bl_010",
+    "name": "Nicolas Braun",
+    "overall": 81,
+    "position": "LB",
+    "nation": "Germany",
+    "league": "Bundesliga",
+    "club": "Rhein United",
+    "pace": 78,
+    "shooting": 52,
+    "passing": 74,
+    "dribbling": 72,
+    "defending": 81,
+    "physical": 78,
+    "rarity": "gold",
+    "image_path": null
+  }
+]