Leaderboard submit and view

[JakeyMarsh1]

As a player, I want to submit my score with a name and see the top 10 so that I can compare with others.

Acceptance Criteria:

• After GameOver, entering a name and submitting writes {name, score, created_at} to the backend; show loading and success/error feedback.​
• High Scores scene fetches and displays top 10 (rank, name, score); shows loading and a clear error or empty state; Back to Menu works.​
• Offline/queueing is out of scope for MVP to reduce complexity.​

Tasks:

• Supabase table: id, name, score, created_at; index for score desc.​
• submitScore(name, score) and getTopScores() utilities.​
• Name input + submit UI in GameOver; HighScoreScene with list and states.​
• Test happy path and error handling quickly