Replace the 3D top-down rendered minimap with WoW's native pre-rendered
BLP tile textures loaded via md5translate.trs. Tiles are composited into
a 3x3 grid FBO with proper axis transposition matching the ADT terrain
convention. The screen shader provides camera-rotation, circular mask,
directional player arrow, and 20% transparency. Minimap is now on by
default with the N toggle key removed.
Centralizes all coordinate conversions in core/coordinates.hpp with
proper canonical WoW coords (+X=North, +Y=West, +Z=Up). Fixes critical
tile calculation bug that was loading wrong surrounding tiles during
terrain streaming, and fixes position sync sending ADT-raw format
instead of canonical coordinates to the server.