Change: Increase house type limit from 512 to 4096. (#12288)

This moves HouseType from m4+m3[6] to m8 making it 'easier' to access.

src/newgrf_house.cpp

@@ -492,7 +492,7 @@ static uint32_t GetDistanceFromNearbyHouse(uint8_t parameter, TileIndex tile, Ho
 				local_houseid = nearby_house_id;
 			} else {
 				local_houseid = (hs->grf_prop.grffile == this->ro.grffile ? 1 : 2) << 8;
-				local_houseid |= hs->grf_prop.local_id;
+				local_houseid |= ClampTo<uint8_t>(hs->grf_prop.local_id); // Spec only allows 8 bits, so all local-ids above 254 are clamped.
 			}
 			return houseclass << 16 | local_houseid;
 		}