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/1978/worldcup.groups.json

@@ -0,0 +1,58 @@
+{
+  "groups": [
+    {
+      "name": "Group 1",
+      "teams": [
+        "Italy",
+        "France",
+        "Argentina",
+        "Hungary"
+      ]
+    },
+    {
+      "name": "Group 2",
+      "teams": [
+        "West Germany",
+        "Poland",
+        "Tunisia",
+        "Mexico"
+      ]
+    },
+    {
+      "name": "Group 3",
+      "teams": [
+        "Austria",
+        "Spain",
+        "Brazil",
+        "Sweden"
+      ]
+    },
+    {
+      "name": "Group 4",
+      "teams": [
+        "Peru",
+        "Scotland",
+        "Netherlands",
+        "Iran"
+      ]
+    },
+    {
+      "name": "Group A",
+      "teams": [
+        "Austria",
+        "Netherlands",
+        "Italy",
+        "West Germany"
+      ]
+    },
+    {
+      "name": "Group B",
+      "teams": [
+        "Brazil",
+        "Peru",
+        "Argentina",
+        "Poland"
+      ]
+    }
+  ]
+}