v0.25.0 — Planet-scale worlds

Multi-continent generation reworked so a world reads as many distinct continents spread across a planet, with latitude-driven climate, ocean islands, and a one-line world preset.

Added

• world preset — full planet in one line (continents=8, sea_level=0.64, continent_spread=0.95, mountain_density=0.7, polar_cold=0.5); best on a wide canvas, e.g. generate(240, 130).
• polar_cold knob (0..1) — size of the polar ice caps. Latitude sets where the cold falls; this sets how much.

Changed

• Continents are scattered swell-clusters of varying size (a few big among several small), reliably separated by open ocean; they may run to any map edge.
• Per-plate Euler-pole rotation → mountain belts vary along their length; boundaries classified convergent/divergent/transform (mountains, rifts, fault valleys).
• Oceans populated with archipelagos and curved volcanic island arcs.
• Latitude-driven temperature with polar ice caps; gentler elevation lapse (no more snow-capped equatorial peaks). desert/arctic/tropical presets gain polar_cold.
• Internal cell cap raised 1500 → 8000 for planet-scale detail (small canvases unaffected).

Compatibility

polar_cold is a trailing WorldMapConfig field — positional construction and existing JSON keys unaffected (to_dict() emits one new key). Single-continent, template, and elevation-hint worlds are byte-unchanged.

Full notes: see CHANGELOG.md.