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/1974/worldcup.groups.json

@@ -0,0 +1,58 @@
+{
+  "groups": [
+    {
+      "name": "Group 1",
+      "teams": [
+        "West Germany",
+        "Chile",
+        "East Germany",
+        "Australia"
+      ]
+    },
+    {
+      "name": "Group 2",
+      "teams": [
+        "Brazil",
+        "Yugoslavia",
+        "Zaire",
+        "Scotland"
+      ]
+    },
+    {
+      "name": "Group 3",
+      "teams": [
+        "Uruguay",
+        "Netherlands",
+        "Sweden",
+        "Bulgaria"
+      ]
+    },
+    {
+      "name": "Group 4",
+      "teams": [
+        "Italy",
+        "Haiti",
+        "Poland",
+        "Argentina"
+      ]
+    },
+    {
+      "name": "Group A",
+      "teams": [
+        "Netherlands",
+        "Argentina",
+        "Brazil",
+        "East Germany"
+      ]
+    },
+    {
+      "name": "Group B",
+      "teams": [
+        "Yugoslavia",
+        "West Germany",
+        "Sweden",
+        "Poland"
+      ]
+    }
+  ]
+}

app/data/wikipedia/1974/worldcup.stadiums.json

@@ -0,0 +1,36 @@
+{
+  "stadiums": [
+    {
+      "name": "Olympiastadion",
+      "city": "Munich"
+    },
+    {
+      "name": "Volksparkstadion",
+      "city": "Hamburg"
+    },
+    {
+      "name": "Waldstadion",
+      "city": "Frankfurt"
+    },
+    {
+      "name": "Westfalenstadion",
+      "city": "Dortmund"
+    },
+    {
+      "name": "Parkstadion",
+      "city": "Gelsenkirchen"
+    },
+    {
+      "name": "Niedersachsenstadion",
+      "city": "Hanover"
+    },
+    {
+      "name": "Rheinstadion",
+      "city": "Düsseldorf"
+    },
+    {
+      "name": "Neckarstadion",
+      "city": "Stuttgart"
+    }
+  ]
+}