Compare views rebuilt: from the zone's view, in sections, one line per record

The Compare views tab and jarl zone diff compare a zone with the same zone in other views from the view you're on: a summary per view, what is answered differently (Use this everywhere), the names only some views have (Add to VIEW), and how many are the same. One name can be compared (jarl zone diff ZONE NAME [TYPE], a Compare button per record). The CLI prints one line per record, cut to the terminal (--wide shows it whole); the web UI cuts long values with the whole one on hover. GET /zones/{zone}/compare returns these sections, with ?with, ?name and ?type.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -37,6 +37,19 @@ All notable changes to Jarl are documented here. The format follows
   delegation and its glue stay.
 - Zone commands take a network for a reverse zone: `jarl zone show
   10.0.10.0/24`.
+- Comparing one name across views: `jarl zone diff adbraun.lol nas [A]`,
+  and a **Compare** button on each record.
+
+### Changed
+
+- **Compare views** and `jarl zone diff` are rebuilt around the view
+  you're on (docs/views.md#comparing-views): a summary per view, then
+  what is answered differently (a view's own records in linked zones,
+  drift otherwise) with **Use this everywhere**, the names only some
+  views have, grouped, with **Add to VIEW**, and how many are the same.
+  One line per record: the CLI cuts long TXT records to the terminal
+  (`--wide` shows them whole). `--with` picks the views to compare with.
+  `GET /zones/{zone}/compare` returns these sections instead of `rows`.
 
 ### Fixed