Increase terrain load radius during taxi flights to fix missing tiles

Load radius was reduced to 3 during taxi (from 4 normal), causing
tiles to not load fast enough at 32 u/s flight speed. Increased to 6
and restored update interval to 0.033s for responsive tile detection.

Disable WMO/M2 camera collision raycasts

Camera collision with WMO walls and M2 doodads caused erratic zoom
and pull-through at doorway transitions. Terrain-only camera floor
clamping is retained.

Fix loading screen graphical artifacts on window resize

Recreate Vulkan swapchain in LoadingScreen::render() when the dirty flag
is set, so resizing the window during world loading no longer renders
into a stale swapchain with mismatched framebuffers.

Fix Windows release packaging: replace rsync/7z with cp/zip

MSYS2 doesn't have rsync or 7z by default. Use cp -r for assets
and install zip package for archive creation.