docs: Restructure README to introduce dependency resolution modes in basic usage

Major restructuring:
- Move dependency resolution mode explanations from advanced to basic usage section
- Add comprehensive "Understanding Dependency Resolution Modes" subsection
- Clearly explain Version field (SemVer) vs Tag field (Agnostic) in dependency files
- Reorganize content flow: basic concepts → advanced multi-repository scenarios

Content enhancements:
- Explain how both modes examine git tags for selection decisions
- Add detailed Version field patterns (x.y.z, x.y.*, x.*) with examples
- Clarify Tag field usage for exact version specification
- Enhanced configuration examples showing both modes clearly
- Add mixed mode support documentation

Documentation improvements:
- Update dependencies.json description to specify it contains repository dependencies
- Add Version Management Rules for Agnostic mode maintenance
- Include Checkout Tag Selection Algorithm explanation
- Reorganize advanced sections to focus on multi-repository conflict resolution
- Preserve all technical details while improving information architecture

Structure changes:
- Basic Usage now comprehensively covers both dependency resolution modes
- Advanced sections focus on recursive processing and shared dependency resolution
- Clear separation between single-repository and multi-repository scenarios
- Improved examples progression from simple to complex configurations

Additional updates:
- Create updated comparison guide emphasizing SemVer capabilities
- Generate LinkedIn announcement post for open source release
- Provide GitHub topics recommendations for repository discoverability

The README now introduces users to dependency resolution concepts immediately
rather than requiring them to discover these critical concepts in advanced sections.

Author: AndreaV-Lsi