v0.22.0 — Settlement purpose + landmarks

Tell a town what it's for. A new purpose gives it a central landmark the main roads converge on, and biases its districts toward its role — fortress, temple town, mining camp, and more.

Added

• SettlementConfig.purpose — "general" (default), or "trade", "fortress", "religious", "harbor", "extraction", "transit". Anything but general:
  • promotes the central ward to a purpose-specific landmark kind — fortress→citadel, religious→temple, trade→market, harbor→docks, extraction→mine, transit→plaza;
  • focuses the main roads on that landmark (they radiate from it to the gates);
  • biases the ward-kind mix toward the purpose (e.g. fortress → more garrison wards);
  • is drawn with a ★ glyph over the landmark ward.
• New public type Landmark and Settlement.landmark field.
• New presets fortress_town, pilgrimage_site, mining_camp, and a fortress-town gallery showcase.

Compatibility

• purpose="general" output is byte-identical to v0.21.0 (no landmark, unchanged ward bag and roads).
• Settlement serialisation bumps to mapwright/settlement@5, back-compatible — older payloads load with no landmark and purpose="general".
• Public API gains one name: Landmark (minor bump per SemVer).

Full changelog: v0.21.0...v0.22.0