gtdb_ground.py --emit-yaml and --apply dump at different widths, producing wrapped blocks

[realmarcin]

Found reviewing PR #379, and the root cause of the corruption that PR had to fix.

apply_to_community dumps blocks with width=4096, so each key is one line. The --emit-yaml path dumps at the default width (~100), so long scalars — gtdb_lineage, mapping_source — wrap onto continuation lines indented deeper than the block keys.

13 records in kb/communities/ carry such a wrapped block today, pasted in from --emit-yaml output.

That inconsistency is what made #378 hard: any line-level editor has to handle both shapes, and the first version matched exactly six spaces and orphaned the continuations into duplicate keys. --refresh now normalises them (the swept diff is net −30 lines, all unwrapping), but the two paths still disagree, so a fresh --emit-yaml paste reintroduces the shape.

Fix: dump at the same width in both paths — width=4096 in _block's --emit-yaml rendering — so a pasted block is byte-identical to an applied one.

Secondary, worth considering with it: --refresh without --apply is silently a no-op, and --refresh with --ncbi-id/--name is silently ignored. Argparse enforces neither.