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/2014/worldcup.stadiums.json

@@ -0,0 +1,60 @@
+{
+  "stadiums": [
+    {
+      "name": "Estádio Mineirão",
+      "city": "Belo Horizonte"
+    },
+    {
+      "name": "Estádio do Maracanã",
+      "city": "Rio de Janeiro"
+    },
+    {
+      "name": "Estádio Castelão",
+      "city": "Fortaleza"
+    },
+    {
+      "name": "Itaipava Arena Pernambuco",
+      "city": "Recife"
+    },
+    {
+      "name": "Estádio Nacional Mané Garrincha",
+      "city": "Brasília"
+    },
+    {
+      "name": "Estádio Beira-Rio",
+      "city": "Porto Alegre"
+    },
+    {
+      "name": "Arena Corinthians",
+      "city": "São Paulo"
+    },
+    {
+      "name": "Itaipava Arena Fonte Nova",
+      "city": "Salvador"
+    },
+    {
+      "name": "Maracanã Stadium",
+      "city": "Rio de Janeiro"
+    },
+    {
+      "name": "Arena de São Paulo",
+      "city": "São Paulo"
+    },
+    {
+      "name": "Arena das Dunas",
+      "city": "Natal"
+    },
+    {
+      "name": "Arena da Amazônia",
+      "city": "Manaus"
+    },
+    {
+      "name": "Arena Pantanal",
+      "city": "Cuiabá"
+    },
+    {
+      "name": "Arena da Baixada",
+      "city": "Curitiba"
+    }
+  ]
+}