Add comprehensive target configuration parsing and inheritance system:
- Create internal/targets package with config structures
- Support JSON configuration loading with inheritance resolution
- Implement multi-level inheritance (e.g., rp2040 → cortex-m0plus → cortex-m)
- Add 206 target configurations from TinyGo for embedded platforms
- Support core fields: name, llvm-target, cpu, features, build-tags, goos, goarch, cflags, ldflags
- Provide high-level resolver interface for target lookup
- Include comprehensive unit tests with 100% target parsing coverage
This foundation enables future -target parameter support for cross-compilation
to diverse embedded platforms beyond current GOOS/GOARCH limitations.
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
