Fix: Update Galaxy Brain achievement requirements

[mitss1]

🎯 Summary

Updates the Galaxy Brain badge description to reflect current GitHub policy changes.

🐛 Problem

The README incorrectly stated that Galaxy Brain badges are earned through GitHub's Community Discussions forum.
However, GitHub has disabled achievements in this forum to prevent coordinated/inauthentic activity.

✅ Solution

• Updated Galaxy Brain description to clarify it can be earned in repository discussions
• Added explicit note that Community Discussions forum is excluded
• Maintains accuracy while preserving helpful information

🔗 References

• GitHub Community Discussion about Galaxy Brain
  requirements

[mirkashi]

fix(achievements): update Galaxy Brain achievement requirements

• Adjusted criteria for Galaxy Brain to better reflect intended difficulty
• Updated requirement thresholds in achievement logic
• Synced in-game description with new requirements

If you share the old requirement and the new one you want, I can rewrite this commit so it’s super specific (e.g., “reduced from 50 moves to 30 moves” etc.).

[mitss1]

fix(achievements): update Galaxy Brain achievement requirements

• Adjusted criteria for Galaxy Brain to better reflect intended difficulty

• Updated requirement thresholds in achievement logic

• Synced in-game description with new requirements

If you share the old requirement and the new one you want, I can rewrite this commit so it’s super specific (e.g., “reduced from 50 moves to 30 moves” etc.).

Thanks for the feedback! Here are the concrete before/after requirements:
• Old requirement: “2 accepted answers in Community Discussions.”
• New requirement: “2 accepted answers in repository Discussions (the central Community forum no longer counts since achievements are disabled there).”

Reference: GitHub has disabled achievements in the main Community forum, so the Galaxy Brain badge can now only be obtained through repo-level Discussions.