Reverse zones: other views' addresses aren't missing PTRs

A reverse zone's missing PTR count covers only its own view's A and
AAAA records. Addresses only other views' records use are counted apart
(ptr_other_views, 'Other views' in zone show, a note on the zone page)
and filled only when asked: fill-ptr --other-views, zone create
--fill --other-views, or the New reverse zone dialog's checkbox. This
keeps one view's host names out of another view's reverse zones.

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

internal/api/types.go

@@ -48,6 +48,10 @@ type Zone struct {
 	// PTRMissingList are the first 25 of them: the PTR records adding
 	// them would create.
 	PTRMissingList []PTRFill `json:"ptr_missing_list,omitempty"`
+	// PTROtherViews counts the addresses in it, without a PTR record,
+	// that only other views' records use: not missing, but fill-ptr with
+	// other_views=1 can name them from there.
+	PTROtherViews int `json:"ptr_other_views,omitempty"`
 	// Pending is set when listing with a changeset: add, change or delete.
 	Pending string `json:"pending,omitempty"`
 }