📦 Improve Documentation and Test Coverage for JToon

Summary

This PR enhances the JToon library with comprehensive POJO test coverage, improved documentation structure, and better developer experience for local builds.

Changes

🧪 Enhanced Test Coverage

• Added 17 new test cases covering POJO encoding scenarios
• Created dedicated TestPojos.java with test record classes for:
  • Simple POJOs with basic fields
  • Nested object structures
  • Collections (Lists and Maps)
  • Jackson annotations (@JsonProperty, @JsonIgnore)
• Tests validate proper encoding of POJOs in both standalone and tabular formats
• All tests organized in nested JUnit 5 test classes for better readability

📚 Documentation Improvements

• Extracted TOON specification into dedicated TOON-SPECIFICATION.md (743 lines)
  • Complete format rules and canonical formatting guidelines
  • Detailed benchmarks and accuracy measurements
  • Comprehensive quoting rules and examples
  • LLM usage recommendations
• Streamlined README.md (reduced by ~450 lines)
  • Focused on quick start and practical usage
  • All code examples now use Java records instead of verbose Map constructions
  • Cleaner, more modern examples that better represent typical Java usage
  • Links to full specification for detailed information

🔧 Developer Experience

• Modified build.gradle to enforce Java 21 toolchain only in CI environments
• Local developers can now use their installed JDK version
• Improves local development workflow while maintaining CI build consistency

Examples of Updated Code Style

Before (verbose Map construction):

Map<String, Object> user = new LinkedHashMap<>();
user.put("id", 123);
user.put("name", "Ada");
user.put("tags", List.of("reading", "gaming"));

After (clean records):

record User(int id, String name, List<String> tags) {}
User user = new User(123, "Ada", List.of("reading", "gaming"));

Files Changed

• build.gradle - Conditional Java toolchain enforcement
• README.md - Streamlined and modernized with record examples
• TOON-SPECIFICATION.md - New comprehensive format specification
• src/test/java/com/felipestanzani/jtoon/JToonTest.java - Added POJO test suite
• src/test/java/com/felipestanzani/jtoon/TestPojos.java - New test record classes

Testing

All existing tests pass, plus 17 new test cases added covering POJO encoding scenarios.

Breaking Changes

None. This is a non-breaking enhancement that improves documentation and test coverage.

Summary by CodeRabbit

• Documentation

  • Reorganized README with consolidated reference to new TOON Format Specification for detailed rules and examples.
  • Added comprehensive TOON-SPECIFICATION.md covering syntax, formatting rules, LLM prompt conventions, and example transformations.

• Tests

  • Expanded test coverage with comprehensive test suite for Plain Old Java Objects, nested structures, Jackson annotations, and container formats.

• Chores

  • Updated build configuration for conditional JDK toolchain enforcement.