docs: Reorganize documentation to prioritize SemVer mode over Agnostic mode

- Reorder Migration and Dependency Management Guide sections:
  * SemVer migration and version changes now presented first
  * Agnostic mode sections follow as alternative approach
  * Updated cross-references and comparative language throughout

- Restructure main README for improved clarity:
  * Position SemVer mode as primary/recommended approach
  * Present floating version patterns prominently in examples
  * Update configuration examples to lead with SemVer capabilities
  * Clarify that -ApiCompatibility parameter applies only to Agnostic mode

- Enhance documentation flow and consistency:
  * Fix cross-references to migration guide sections
  * Update decision matrices to favor SemVer for modern projects
  * Improve example progression from automated to explicit control
  * Align all references with reordered structure

- Technical improvements:
  * Emphasize zero-maintenance benefits of floating versions
  * Clarify mode-specific behaviors and parameters
  * Update troubleshooting sections for better mode distinction
  * Enhance best practices guidance for mode selection

This reorganization positions SemVer with floating versions as the modern,
automated dependency management approach while maintaining comprehensive
coverage of Agnostic mode for specific use cases requiring explicit control.

Author: AndreaV-Lsi