docs(readme): update main index for Phase 5 completion

[apenlor]

Objective

This PR updates the README.md on the main branch to its "Master Index" format, following the merge and tagging of the Phase 5 feature branch.

Key Changes

• The "Workshop Guide" table has been updated with a new, completed row for Phase 5: Correlated Logs & Access Auditing. This includes direct links to the v5.0-correlated-logs-auditing tag and the merged Pull Request (#12).
• The main "Running the Project" call-to-action link at the bottom of the file has been updated to point to the quick-start guide for the new, current phase (v5.0-correlated-logs-auditing).

This brings the project's primary documentation into its final, correct state for this phase, serving as a clean entry point for the next stage of the lab.