fix(dns plugin): shorten machine-written names in the default table

[scotwells]

Excluding the records Datum manages fixed one zone's width but not the general case: any system that writes into DNS puts an encoded identifier in the owner name, and Datum does not label a third party's records as managed. In prism, 1093 of the long names come from external-dns and count as your own.

Names split cleanly into two populations:

written by	shape	length
people	@, www, _dmarc, _acme-challenge, selector1._domainkey	1–20
machines	hex digest / UUID / base32 public key	32 / 36 / 52

40 sits in the gap, so a hand-written name is shown whole and an encoded one is cut. Measured against real zones, every hand-authored name in datum-staging.net fits — median 11, longest exactly 40.

Names cost more to cut than values

A name is an argument — record describe and record delete both take one — so shortening it can leave a row you cannot act on. Three things keep that honest:

• the footer counts names separately from values, so a shortened name is never silent
• -o wide and -o json carry names in full
• -o name is never shortened, since it exists precisely to turn a row back into something you can pass to describe or delete

Effect

Both zones now render at 151 columns, down from 180 and 166, and the width no longer depends on what a connector happened to name a record.

Worth noting for later: the widest remaining contributor is now STATUS, where a provenance marker like Programmed (managed by AI Edge) is 32 characters.

Related

Three readability fixes for datumctl dns record list, reviewed and merged bottom-up:

1. fix(dns plugin): shorten long record values in the default table #107 — shorten long values (base: main)
2. feat(dns plugin): add --no-managed to list only your own records #108 — --no-managed to hide records another system writes
3. fix(dns plugin): shorten machine-written names in the default table #109 — shorten machine-written names

All three follow #102, which added the plugin, and are UX fixes found while using it against real staging zones. The plugin ships from #106's release plumbing and is installed via datum-cloud/datumctl-plugins#22.

Written after #108 proved insufficient for prism, where 1093 long names come from external-dns and count as your own.