fix: extend group heading regex from [a-h] to [a-z] for 2026 Groups I-L

2026 FIFA World Cup has 12 groups (A-L). The previous regex only matched A-H,
causing Groups I, J, K, L to fall through undetected and collapse into Group H.

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

lib/wiki-scraper.ts

@@ -250,7 +250,7 @@ function processHeading(text: string, level: number, state: State): void {
   }
   if (!state.active) return
   if (level === 3 || level === 4) {
-    if (/^group [a-h1-9]+$/i.test(t)) {
+    if (/^group [a-z1-9]+$/i.test(t)) {
       state.group = text.trim()
     } else if (/round of 32/i.test(t)) {
       state.round = 'Round of 32'; state.group = null