Coupling doesn't support some block sizes

[anton-seaice]

There are some block sizes which can be set in cice, but then don't run in other components.

This is the new default for esm1.6:

cice5:
      require:
        - '@2026.01.000'
        - 'nxglob=360 nyglob=300 blckx=30 blcky=300 mxblcks=1' # grid size and block size

but setting blckx=36 fails (without changing the runtime nprocs) fails for unknown reasons:

ACCESS-NRI/access-esm1.6-configs#403 (comment)

(related to https://github.com/ACCESS-NRI/UM7/issues/151)

Other scenarios also fail:

ACCESS-NRI/access-spack-packages#329 (comment)

Does setting blckx as a integer divisor of nxglob and setting nprocs consistently always work ?

[anton-seaice]

Also this gem:

cice5/drivers/access/cpl_interface.F90

Lines 828 to 830 in bd291fb

	#if (MXBLCKS != 1)
	#error The following code assumes that max_blocks == 1
	#endif