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/1994/worldcup.stadiums.json

@@ -0,0 +1,40 @@
+{
+  "stadiums": [
+    {
+      "name": "Soldier Field",
+      "city": "Chicago"
+    },
+    {
+      "name": "RFK Stadium",
+      "city": "Washington, D.C."
+    },
+    {
+      "name": "Cotton Bowl",
+      "city": "Dallas"
+    },
+    {
+      "name": "Rose Bowl",
+      "city": "Pasadena"
+    },
+    {
+      "name": "Citrus Bowl",
+      "city": "Orlando"
+    },
+    {
+      "name": "Stanford Stadium",
+      "city": "Stanford"
+    },
+    {
+      "name": "Foxboro Stadium",
+      "city": "Foxborough"
+    },
+    {
+      "name": "Giants Stadium",
+      "city": "East Rutherford"
+    },
+    {
+      "name": "Pontiac Silverdome",
+      "city": "Pontiac"
+    }
+  ]
+}