Replace embedded resource text files with inline data for Intl CLDR data

[lahma]

Summary

• Convert 6 of 7 embedded .txt resource files in Jint/Native/Intl/Data/ to inline static readonly dictionary initializers in companion .Data.cs partial class files
• Eliminates runtime text parsing, StreamReader allocations, and reflection-based GetManifestResourceStream calls
• LikelySubtags.txt (133 KB) kept as embedded resource — inline would add ~217 KB to DLL due to UTF-16 string encoding; its loader fixed from non-thread-safe ??= to Lazy<T>
• ComplexLanguageMapping and VariantMapping converted to readonly record struct with primary constructors
• All dictionary initializers use exact-count capacity to avoid rehashing

Benchmark Results (BenchmarkDotNet, net10.0)

Before (embedded resources)

Method	Mean	Allocated
IntlNumberFormat	98.784 μs	31.03 KB
IntlDateTimeFormat	8.561 μs	29.34 KB
IntlListFormat	7.341 μs	26.41 KB
IntlRelativeTimeFormat	104.523 μs	29.07 KB
LocaleCanonicalization	8.622 μs	36.92 KB

After (inline data)

Method	Mean	Allocated
IntlNumberFormat	93.470 μs	31.03 KB
IntlDateTimeFormat	8.301 μs	29.34 KB
IntlListFormat	7.008 μs	26.41 KB
IntlRelativeTimeFormat	90.978 μs	29.07 KB
LocaleCanonicalization	9.576 μs	36.92 KB

Summary

Metric	Change
IntlNumberFormat	-5.4% faster
IntlDateTimeFormat	-3.0% faster
IntlListFormat	-4.5% faster
IntlRelativeTimeFormat	-13.0% faster
LocaleCanonicalization	+11.1% (uses Lazy<T> now for thread safety)
Memory allocations	No change across all benchmarks
DLL size (net8.0)	+9,728 bytes (+0.5%, from 1,878,016 to 1,887,744)

Test plan

• dotnet test Jint.Tests — 2764+2717 passed, 0 failed
• dotnet test Jint.Tests.Test262 — 93,300 passed, 0 failed
• DLL size increase < 1%
• Clean build across all targets (net462, netstandard2.0, netstandard2.1, net8.0, net10.0)

🤖 Generated with Claude Code