fix SSC parser not recognizing comma+comment measure separators

Commas followed by comments (e.g. ',  // measure 1') were not
recognized as measure separators, causing all notes to be parsed
as a single measure with compressed timing. This is why all arrows
spawned at once on most songs (except Get Lucky which had plain
commas).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/game/sscParser.ts

@@ -126,7 +126,7 @@ function parseNoteSection(
   let currentMeasure: string[] = []
 
   for (const line of noteLines) {
-    if (line === ',') {
+    if (line === ',' || line.startsWith(',')) {
       measures.push(currentMeasure)
       currentMeasure = []
     } else if (line.length >= 4 && /^[0-9MLF]+$/.test(line.slice(0, 4))) {