Sprint 2.4: Regional market dynamics — MarketRegion, α-formula pricing, regional events, UI tab

[Copilot]

The market was purely global with no regional price variation. This implements per-region supply/demand with independent price evolution, region-scoped market events, and visible price comparison in the Economy UI.

Core engine (EconomySimulation.js)

• MarketRegion class — independent supply/demand state per good, prices evolve via α-formula:

  price_t+1 = clamp(price_t × (1 + α × (demand − supply) / max(1, supply)), min, max)
  

  α = 0.03 per GAMEPLAY_DATA_MODEL.md §6.1. Supports region-scoped events (shortages, blockades) with full serialize/deserialize.
• MARKET_REGION_DEFS — two pre-defined regions:
  • core_worlds (Kernwelten): manufactured goods surplus, raw material scarcity
  • frontier_sectors (Grenzgebiete): raw material surplus, +20% transport surcharge, finished goods scarce
• GalacticMarket extended — new methods: getRegion(), getRegionPrice(), getAllRegionPrices(), applyRegionalEvent(), tickRegions(). Regions included in serialization.

API (api/market.php)

• New get_region_prices action — returns per-region price breakdown for all goods (or a single good_type). Uses live market_region_quotes rows when available; falls back to supply-bias estimate against the global price.

Frontend

• js/network/api.js — marketRegionPrices(good_type?) method.
• RuntimeEconomyController.js — new "Regional Market" tab: color-coded comparison table (cheapest = green, most expensive = orange) across all regions.

Database (sql/migrate_regional_market_v1.sql)

• market_regions — region registry with transport cost multiplier
• market_region_quotes — live supply/demand/price per (region, good), seeded with asymmetric initial values reflecting each region's economic character
• market_region_events — region-scoped event log

Tests

30 new tests covering MarketRegion α-formula ticking, price clamping, regional events, serialization, and GalacticMarket integration. All 2575 unit tests pass.