src/offline/landuse_inout.F90: Replace write interfaces with direct calls to netCDF

[SeanBryan51]

This change is a bug fix and also a refactor. Currently, enabling the land use scheme (via l_landuse) causes the following error when writing out the land use restart file:

 writing cable restart: land use
 Error writing iveg parameter/variable to output file (SUBROUTINE write_output_p
 arameter_r1)
 NetCDF: Not a valid ID                                                         

This is because the incorrect netCDF file ID is used in cable_output.F90 when writing the land use restart file:

CABLE/src/offline/cable_output.F90

Line 51 in b2d3f8d

INTEGER :: ncid_out, ncid_restart ! output/restart data netcdf file ID

Rather than fixing this directly, this change replaces all calls to cable_write.F90 procedures with direct calls to netCDF. This is done so that in the future we can safely replace cable_output.F90 and cable_write.F90 with a renewed output module as part of the parallel I/O output module changes (see #641 and #655).

Note that the land use scheme is not yet currently functional, even with these changes, as landuse3.F90 is partially implemented.

Type of change

Please delete options that are not relevant.

• Bug fix
• Refactor

Checklist

• The new content is accessible and located in the appropriate section
• I have checked that links are valid and point to the intended content
• I have checked my code/text and corrected any misspellings

Testing

• Are the changes bitwise-compatible with the main branch? If working on an optional feature, are the results bitwise-compatible when this feature is off? If yes, copy benchcab output showing successful completion of the bitwise compatibility tests or equivalent results below this line.

2026-02-05 14:20:00,805 - INFO - benchcab.benchcab.py:380 - Running comparison tasks...
2026-02-05 14:20:00,831 - INFO - benchcab.benchcab.py:381 - tasks: 168 (models: 2, sites: 42, science configurations: 4)
2026-02-05 14:22:56,227 - INFO - benchcab.benchcab.py:391 - 0 failed, 168 passed

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📚 Documentation preview 📚: https://cable--681.org.readthedocs.build/en/681/

[abhaasgoyal]

Overall LGTM, just had couple of queries