Update @gruhn/regex-utils to 2.9.1 and adapt to new AST format

[Copilot]

Updates @gruhn/regex-utils from 2.7.3 to 2.9.1. The new version changes lookahead representation in the AST:

Old format:

{ type: 'lookahead', isPositive: boolean, inner: RegExpAST, right: RegExpAST }

New format:

{ type: 'assertion', direction: AssertionDir, sign: AssertionSign, inner: RegExpAST, outer: RegExpAST }

Changes

• Test adaptation: Added convertFromRegExpAST() to map new assertion format to internal lookahead representation in test comparisons
• Unicode range: Changed alphabet from 0x10FFFF to 0xFFFF to match library's default BMP mode (non-unicode flag behavior)
• Type safety: Import LibCharSet type instead of using any for charset conversion

The internal parser implementation remains unchanged - only test utilities needed updates to handle the new library format.

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[coveralls]

Pull Request Test Coverage Report for Build 22047353374

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 105 unchanged lines in 8 files lost coverage.
• Overall coverage increased (+0.06%) to 90.339%

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Files with Coverage Reduction	New Missed Lines	%
build/zigUnparser.js	1	50.44%
build/dalvikBytecodeParser.js	3	98.27%
build/dalvikBytecodeUnparser.js	8	87.1%
build/dalvikExecutableParser.js	8	91.13%
build/arbitraryJava.js	11	97.69%
build/javaParser.js	14	95.25%
build/regularExpressionParser.js	15	90.81%
build/javaUnparser.js	45	83.23%

Totals
Change from base Build 22045807651:	0.06%
Covered Lines:	18447
Relevant Lines:	20246

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💛 - Coveralls