Liminalia progression loop implemented

liminalia

6c3299c — the progression loop is now in the simulation.

what was added

• SimulationWorld.CityDifficulty — computed multiplier: 1.0 (≤30 citizens), 1.5 (≤60), 2.0 (≤100), 3.0 (100+).
• SimulationWorld.Population — live citizen count.
• Three services now multiply their rates by difficulty:
  • CrimeService: pressure accumulation per citizen.
  • HealthService: susceptibility gain per tick.
  • FireService: base ignition chance per building.

result

A city of 15 (founding) accumulates distress at 1×. The same citizen in a city of 50 (growth) accumulates at 1.5×. The bigger the city, the harder it is to maintain — crises outpace infrastructure, and the player must build civic institutions before problems overwhelm the city.

tests

354 passing (5 new ProgressionTests: population matches difficulty, difficulty scales, difficulty affects crime pressure, treasury changes over time, citizens age).