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/1990/worldcup.stadiums.json

@@ -0,0 +1,56 @@
+{
+  "stadiums": [
+    {
+      "name": "Stadio San Paolo",
+      "city": "Naples"
+    },
+    {
+      "name": "Stadio San Nicola",
+      "city": "Bari"
+    },
+    {
+      "name": "Stadio Delle Alpi",
+      "city": "Turin"
+    },
+    {
+      "name": "San Siro",
+      "city": "Milan"
+    },
+    {
+      "name": "Stadio Luigi Ferraris",
+      "city": "Genoa"
+    },
+    {
+      "name": "Stadio Olimpico",
+      "city": "Rome"
+    },
+    {
+      "name": "Stadio Marc'Antonio Bentegodi",
+      "city": "Verona"
+    },
+    {
+      "name": "Stadio Renato Dall'Ara",
+      "city": "Bologna"
+    },
+    {
+      "name": "Stadio Comunale",
+      "city": "Florence"
+    },
+    {
+      "name": "Stadio delle Alpi",
+      "city": "Turin"
+    },
+    {
+      "name": "Stadio Friuli",
+      "city": "Udine"
+    },
+    {
+      "name": "Stadio Sant'Elia",
+      "city": "Cagliari"
+    },
+    {
+      "name": "Stadio La Favorita",
+      "city": "Palermo"
+    }
+  ]
+}