Achievement milestone reactions

[aebrer]

Summary

Track player progression milestones so the gods can react to significant achievements.

Details

Detect and react to key Minecraft progression moments:

• First diamond mined — Kind God celebration
• First nether portal — Deep God stirs, Kind God warns
• First ender pearl — lore moment about the End
• First enchantment — Kind God comments on the magic
• First death — Kind God mourns
• First blaze kill — progression toward the End begins
• First time below Y=0 — Deep God territory
• Iron armor complete — Kind God approval
• Diamond armor complete — major milestone

Track per-player so each player gets their own milestone reactions. Milestones fire once per player and are persisted to disk.

Changes needed

• Backend: New milestones.py module with per-player tracking and persistence
• Backend (events.py): Check events against milestone conditions
• Backend (main.py): Inject milestone notifications into god tick
• God prompts: Context about player progression level

Complexity

Medium — milestone definitions are simple, but need persistence and per-player tracking.