docs: update README for role-first flow

[Panacota96]

Summary

• Update README to describe the role-first ordered-seat workflow
• Document role pool limits, removed roles, target-dropdown removals, power status controls, and win confirmation
• Refresh gameplay flow and Playwright coverage notes

Verification

• git diff --check

[gemini-code-assist]

Code Review

This pull request updates the README.md to reflect a significant shift in the application's workflow toward a role-first, seat-based setup and a prompt-oriented night phase. Key changes include the removal of player name tracking in favor of seat labels, the introduction of power status tracking for specific roles, and updated gameplay flow descriptions. Review feedback identifies discrepancies between the documentation and the current implementation regarding the classification of the Little Girl role as a passive reminder and the mention of a Win confirmation feature that appears to be missing from the codebase.