v0.27.0 — tectonic worlds + cartography pass

Additive/non-breaking. Named geographic Features + FeatureGenerator, simulated-annealing smart label placement (LabelPlacer), RegionalSVGRenderer cartography options (relief_style hillshade/hachure, scale_bar, compass), tectonic world simulation. Unblocks StoryFlow v1.4.0 F5 hex-overworld cartography.