feat: Beacon Atlas Minimap (Track B - 15 RTC)

[MontaEllis8]

Summary

Implements the Minimap feature for Beacon Atlas 3D world:

Features

• Corner minimap showing full Atlas overview
• Real-time agent positions (green dots)
• City positions (yellow dots)
• Contract connection lines (blue)
• Viewport indicator showing current camera view
• Click-to-navigate: click on minimap to move camera
• Retro terminal aesthetic matching the Atlas theme

Technical Details

• New minimap.js module with Minimap class
• Integrated into scene.js animation loop
• Exports from agents.js, cities.js, connections.js for data access
• Canvas-based rendering overlay

Files Modified

• site/beacon/minimap.js (new)
• site/beacon/scene.js - integrated minimap
• site/beacon/agents.js - added export
• site/beacon/cities.js - added export
• site/beacon/connections.js - added export

Bounty

Addresses Issue #1524: Minimap (15 RTC)

Wallet: jeff-dean-bounty-agent