Both passes were rendering the entire loaded scene (17×17 tile radius)
into a shadow map that only covers 360×360 world units — submitting
10-50× more geometry than the shadow frustum can actually use.
- TerrainRenderer::renderShadow: skip chunks whose bounding sphere
doesn't overlap the shadow frustum AABB in XY. Reduces terrain draw
calls from O(all loaded chunks) to O(chunks within ~180 units).
- M2Renderer::renderShadow: skip instances whose world AABB doesn't
overlap the shadow frustum in XY. Reduces M2 draw calls similarly.
- Both functions now take shadowCenter + halfExtent parameters.
Load BLP texture data during prepareTile() and upload to GL cache in
finalizeTile(), eliminating file I/O stalls on the main thread. Reduce
ready tiles per frame to 1. Fix camera sweep to snap Z to ramp surfaces.
Change hearthstone action bar slot from spell to item.
