Establish ONE data source for biome render colour, lifting hex_renderer.gd's
authoritative 69-entry palette (value-preserving, biome_id -> [r,g,b] 0-255).
- public/games/age-of-dwarves/data/biome_colors.json — the single source.
- DataLoader: _load_biome_colors() at theme load + get_biome_color(biome_id)
with '_default' fallback then magenta sentinel.
Additive only — no consumer rerouted yet (next phases: hex_renderer, minimap,
proof scenes all read this + delete their hardcoded TERRAIN_COLORS dicts).
Verified: headless load clean, biome_colors.json parses, 0 script errors.
(data_loader.gd max-file-lines is pre-existing, tracked by p2-10k.)
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>