Heatmap Bot Update

Things I learned shipping a Discord bot this week:

1. Railway's restart policy can cause rapid reconnects → Discord IP ban.

Set restartPolicyMaxRetries to 3, not 5. The fewer restarts, the less likely you get rate limited.

2. SQLite is fine for a Discord bot.

WAL mode + aiosqlite = zero issues so far. You don't need Postgres until you're at hundreds of servers with heavy concurrent writes.

3. discord.py slash commands take up to 1 hour to propagate globally.

For instant updates during development, sync to a specific guild instead. But remove guild sync before production or you get duplicates.

4. matplotlib heatmaps are slower than expected (~300ms per render).

Added a global render rate limiter to prevent queue buildup under load. Small optimization, big difference when multiple servers run /heatmap simultaneously.