The previous rule 'pack/overrides/' ignored the whole directory, which
made it impossible to re-include subpaths via ! exception (git's rule).
Narrow the ignore to 'pack/overrides/mods/' -- the only path that
Build-Tweaks.ps1 actually writes -- and drop the broken whitelist
block. Other subdirs under pack/overrides/ (defaultconfigs/, etc.) now
live in git like normal source.
Adds the Waystones override that 0.16.1 attempted (spawnInVillages =
DISABLED). Bumps to 0.16.3 so launcher caches re-sync.
