fix: eliminate nested quantifiers in separator regex to prevent JIT stack overflow

Each branch in the separator group now matches exactly one character,
with the outer {0,3}? handling repetition. Removes redundant (?:\s)
alternative since \s is already in the character class.

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

Author: deemonic

src/Core/Matchers/RegexMatcher.php

@@ -29,9 +29,9 @@ public function generateSeparatorExpression(array $separators): string
     {
         $normalSeparators = array_filter($separators, fn($sep) => $sep !== '.');
 
-        $pattern = $this->generateEscapedExpression($normalSeparators, self::ESCAPED_SEPARATOR_CHARACTERS);
+        $pattern = $this->generateEscapedExpression($normalSeparators, self::ESCAPED_SEPARATOR_CHARACTERS, '');
 
-        return '(?:' . $pattern . '|\.(?=\w)|(?:\s)){0,3}';
+        return '(?:' . $pattern . '|\.(?=\w)){0,3}?';
     }
 
     public function generateSubstitutionExpressions(array $substitutions): array