Issue #5: V6 Architecture & Feature Documentation (README.md)

[genes3e7]

Description: The V5 Advanced Grouping Engine introduces breaking changes to the data schema and optimization constraints. The root README.md must be updated to reflect these changes to prevent user confusion and document the new constraint resolution mechanics.

Technical Tasks:

• Update the "How It Works" section to document the new dynamic schema (Sep, Grp, ScoreN).
• Document the new "Custom Group Sizes" array input.
• Explain the Soft vs. Hard constraint logic (Conflict Resolution between Sep and Grp).
• Update the Mermaid sequence diagram in the README to reflect the multi-score weighting and soft-constraint penalty evaluation loop.
• Regenerate the project structure block using tools/update_readme.py if new modules were added during V5 implementation.