[codex] Speed up everyone image

[maxbbraun]

Summary

• Speed up the everyone image by caching rendered outputs and sharing cached map generation across instances.
• Reduce cold marker-generation work by fetching only user home fields, using coordinate-only geocoding, and deduplicating identical city markers.
• Add map download timeout/status handling while preserving copy safety for cached PIL images.

Root Cause

The everyone image performed unnecessary work on cold generation: full geocoder lookups also fetched timezone/elevation metadata, duplicate city markers were kept, and map-image caching was tied to object identity.

Validation

• venv/bin/python -m compileall -q . -x './venv'
• Mocked hot-path checks for marker generation, lightweight geocoder reuse, everyone image caching/copy safety, and Google map cache/copy safety were run locally before publishing.