Validate date requested aligns with SMIPS collection extent
Source:R/read_smips.R
dot-check_collection_agreement.RdSMIPS daily COGs are published from 2015-01-01 (the earliest archived
complete set of soil moisture GeoTIFFs available on the TERN Data Portal),
up to today. Requests outside that window will definitely return HTTP 404
from the GDAL vsicurl driver, resulting in a "file does not exist" error
from terra::rast(). This helper function catches this case before
any network I/O. (Note: the requested rasters may still be unavailable
even if this check passes, e.g., if the user has requested a very recent
raster that has not been added to the TERN server yet. This validation
function simply checks for the obviously impossible cases.)