Add benchmark module for comparing JSON5 vs JSON serialization performance

[Copilot]

This PR adds a comprehensive benchmarking module to compare the performance of JSON5 serialization/deserialization against standard JSON using kotlinx.serialization.

What's Added

New benchmark Module

• Location: benchmark/ directory with complete Gradle module setup
• Purpose: Performance comparison between JSON5 and standard JSON serialization
• Dependencies: Uses existing lib module and kotlinx.serialization

Benchmark Features

• Tests multiple data types: simple objects, complex nested structures, collections, and large lists
• Configurable iteration counts (default: 1000 iterations per test)
• JVM warmup to ensure accurate measurements
• Generates both CSV and human-readable summary reports

Test Data Types

• SimplePerson: Basic data class with name, age, boolean
• ComplexPerson: Nested object with address, phone numbers, skills, metadata
• Company: Large structure with employees and departments
• NumberTypes: Various numeric types (int, long, double, float, byte, short)
• CollectionTypes: Lists, maps, and nested collections
• Bulk collections: Lists of 50-100 objects for scale testing

Generated Reports

# Run benchmarks
./gradlew :benchmark:run

# Generates:
benchmark_results_YYYY-MM-DD_HH-mm-ss.csv    # Detailed timing data
benchmark_summary_YYYY-MM-DD_HH-mm-ss.txt    # Performance comparisons

Sample Results

Based on typical runs, standard JSON consistently outperforms JSON5:

SimplePerson Serialization: JSON5=0.031ms, JSON=0.012ms (JSON 2.6x faster)
ComplexPerson Serialization: JSON5=0.081ms, JSON=0.016ms (JSON 5.1x faster)  
Company Serialization: JSON5=0.189ms, JSON=0.030ms (JSON 6.3x faster)

Files Added

• benchmark/build.gradle.kts - Module build configuration
• benchmark/src/main/kotlin/.../BenchmarkRunner.kt - Main benchmark execution
• benchmark/src/main/kotlin/.../SerializationBenchmark.kt - Core benchmarking logic
• benchmark/src/main/kotlin/.../TestData.kt - Data models for testing
• benchmark/src/main/kotlin/.../TestDataGenerator.kt - Test data creation
• benchmark/src/test/kotlin/.../BenchmarkTest.kt - Unit tests
• benchmark/README.md - Documentation and usage instructions

Configuration Updates

• Updated settings.gradle.kts to include benchmark module
• Updated .gitignore to exclude generated benchmark reports

The benchmark provides valuable insights into JSON5 performance characteristics and can be used to track performance improvements over time.

Fixes #14.

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[hossain-khan]

[hossain-khan]

benchmark_results_2025-06-09_00-14-01.csv
benchmark_summary_2025-06-09_00-14-02.txt

[hossain-khan]

Fantastic! 🤩