Add district simulation core for scope A foundation

[iamlukethedev]

Summary

• add deterministic district simulation engine for Scope A foundations
• model 10-district neighborhood simulation with 10-agent cap defaults
• include housing (rooms/rent), schedules, needs, relationships, and economy updates per tick
• add unit tests to validate deterministic creation/reconcile/step behavior and need emoji mapping
• wire simulation into RetroOffice3D with a visible city HUD panel that shows day/time, district population, economy/relations, housing, and needs alerts
• shift the scene from office-first to city-first rendering using a full tile-grid city layout
• add SimCity-inspired roads, intersections, mixed zoning, greenery, and animated traffic
• suppress office/onboarding blockers in city mode so the city view is exposed cleanly by default
• add Phase 1 HQ interaction: click HQ from the city to enter the office interior, with a Back to City control

Walkthrough

full_city_browser_render_demo.mp4
full city latest clean screenshot

Testing

• npm run typecheck

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