refactor: rename data/openfootball → data/wikipedia, drop data/kaggle

Move world_cup.csv to app/data/ directly (the only remaining Kaggle file
used by seed.ts for tournament metadata). Delete the rest of the Kaggle CSVs.
Update path constants in scrape-wikipedia.ts and seed.ts accordingly.

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

app/data/wikipedia/1938/worldcup.stadiums.json

@@ -0,0 +1,48 @@
+{
+  "stadiums": [
+    {
+      "name": "Parc des Princes",
+      "city": "Paris"
+    },
+    {
+      "name": "Vélodrome Municipal",
+      "city": "Reims"
+    },
+    {
+      "name": "Stade Gerland",
+      "city": "Lyon"
+    },
+    {
+      "name": "Stade du T.O.E.C.",
+      "city": "Toulouse"
+    },
+    {
+      "name": "Stade Olympique de Colombes",
+      "city": "Colombes"
+    },
+    {
+      "name": "Stade Vélodrome",
+      "city": "Marseille"
+    },
+    {
+      "name": "Stade de la Meinau",
+      "city": "Strasbourg"
+    },
+    {
+      "name": "Stade municipal",
+      "city": "Le Havre"
+    },
+    {
+      "name": "Stade Victor Boucquey",
+      "city": "Lille"
+    },
+    {
+      "name": "Stade du Fort Carré",
+      "city": "Antibes"
+    },
+    {
+      "name": "Parc Lescure",
+      "city": "Bordeaux"
+    }
+  ]
+}