fix: retry failed group subpages, add rate-limit detection in scraper

- Detect Wikipedia plain-text rate-limit response ("You are making too many
  requests") and wait 30s before retrying, rather than silently failing
- Increase inter-attempt delay from 3s to 15s per attempt
- Increase group subpage delay from 1.2s to 3s, year delay from 0.6s to 2s
- Re-scrape 1982, 1998, 2002, 2006 which had failed groups; all groups now
  complete — e.g. 2002 now has 64 matches including Group E (Germany/Klose)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

data/2002/worldcup.stadiums.json

@@ -77,17 +77,29 @@
       "city": "Ulsan"
     },
     {
-      "name": "Kashima Soccer Stadium",
-      "city": "Ibaraki"
-    },
-    {
-      "name": "Wing Stadium",
-      "city": "Kobe"
+      "name": "Niigata Stadium",
+      "city": "Niigata"
     },
     {
       "name": "Sapporo Dome",
       "city": "Sapporo"
     },
+    {
+      "name": "Kashima Soccer Stadium",
+      "city": "Ibaraki"
+    },
+    {
+      "name": "Ecopa Stadium",
+      "city": "Shizuoka"
+    },
+    {
+      "name": "International Stadium Yokohama",
+      "city": "Yokohama"
+    },
+    {
+      "name": "Wing Stadium",
+      "city": "Kobe"
+    },
     {
       "name": "Niigata Big Swan Stadium",
       "city": "Niigata"
@@ -96,10 +108,6 @@
       "name": "Ōita Big Eye Stadium",
       "city": "Ōita"
     },
-    {
-      "name": "International Stadium Yokohama",
-      "city": "Yokohama"
-    },
     {
       "name": "Shizuoka Ecopa Stadium",
       "city": "Fukuroi, Shizuoka"