Linked zones: PTR records follow each view, deleting an override stays deleted

Auto-PTR (and --ptr) changed PTR records in every linked view, whatever
view the address record was in. ptrSync now compares each touched A/AAAA
set before and after, per view, and changes only that view's reverse
zone. PTR records in linked reverse zones are local (fill too); a shared
PTR set is made local in each view before one view changes it.

Deleting a linked zone's local records no longer brings the shared ones
back into the view: the name and type are gone from that view and the
other views keep theirs, local to each. Share still restores.

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

docs/views.md

@@ -183,7 +183,9 @@ own and its own zone options.
   the web UI). A local record overrides the shared records of the same name
   and type in that view: `www A 10.0.10.5` local to internal, while the
   external view keeps the shared `www A 203.0.113.20`. Delete the local
-  records and the view gets the shared ones back.
+  records and the name and type are gone from that view only: the other
+  views keep their records, each local to its view now. To give the view
+  the shared version back instead, **Share** it from a view that has it.
 * A new record joins the set of the same name and type: local if that set
   is local in its view, shared otherwise.
 * **Sharing a version** (`jarl record update ID --shared`, **Share** in the