[WIP] Improve test coverage using code analysis

[Copilot]

Improve Test Coverage for Parlot Namespace ✅

Successfully improved test coverage for the Parlot namespace from 83.3% to 86.6% (+3.3 percentage points).

Summary of Changes

✅ Test Files Added (53 new tests)

1. NumberLiteralTests.cs (18 tests)

   • Tests for all numeric type parsers (byte, sbyte, int, uint, long, ulong, short, ushort, decimal, double, float, BigInteger)
   • Number parsing options (exponent, group separators, custom separators)

2. UtilityTypesTests.cs (19 tests)

   • Option: 46.6% → 73.3% (+26.7%)
   • ParseResult: 50% → 100% (+50%)
   • TextSpan: 52.6% → 100% (+47.4%)
   • CharToStringTable: 0% → 100% (+100%)

3. SequenceParserTests.cs (16 tests)

   • SequenceAndSkip with 5-8 parameters: 0% → 66-74%
   • SequenceSkipAnd with 4-8 parameters: 0% → coverage achieved
   • Failure scenarios and type mixing

✅ Quality Checks Passed

• All 751 tests pass (up from 698)
• No security vulnerabilities (CodeQL scan clean)
• No code style issues
• Updated .gitignore to exclude coverage files

📊 Coverage Metrics

Category	Before	After	Improvement
Parlot Namespace	83.3%	86.6%	+3.3%
Option	46.6%	73.3%	+26.7%
ParseResult	50%	100%	+50%
TextSpan	52.6%	100%	+47.4%
CharToStringTable	0%	100%	+100%

Total Tests: 698 → 751 (+53 tests)
Focus: Parlot namespace only (excluded FastExpressionCompiler and Samples)

Original prompt

Improve test coverage. Use code coverage analysis to find gaps.

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