[codex] Document Tokamax RTX GPU compatibility

[DimaMolod]

Summary

• Reword the slurm_exclude_nodes guidance so RTX PRO 6000 / Blackwell exclusion is documented as an old/pre-Tokamax container workaround.
• Keep the exclusion mechanism documented for genuinely incompatible old images or local builds, but make clear that the permanent fix is the updated AlphaFold 3 / Tokamax stack.
• Update the memory-resource test comment to match the new intent without changing behavior.

Context

The AlphaPulldown AF3 submodule update targets official AF3 v3.0.2, which includes the compatibility work requested in google-deepmind/alphafold3#394.

Official AF3 history used as evidence:

• 3890782: migrated AF3 to tokamax.gated_linear_unit and tokamax.dot_product_attention.
• 608edb6: updated to Tokamax 0.0.11 and JAX 0.9.1.
• f6a5aec: official v3.0.2, containing both commits.

Coordinates with AlphaPulldown PR KosinskiLab/AlphaPulldown#623.