feat(simulation): add server/src/atlas/ — full Phase 1 generation pipeline
Ten-module atlas package implementing the D-194–D-218 district generation
stack: heightmap loader, BodyWorldState LRU cache, D8 drainage routing,
background generation queue, five-phase attractor-matching, three-component
district mix, block irregularity, tile condition thresholds, and the Phase 1
skeleton generator that wires them into DistrictSkeleton.
Closes #916 #917 #918 #919 #920 #922 #923 #924 #899.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>