Linked zones: shared records kept in step across views

Zones of the same name in different views can be linked. Shared records
are kept in step: a change in one view reaches the others in the same
changeset, as explicit operations, so the diff, permission checks,
history and undo cover every view. Records local to a view override the
shared records of that name and type there; removing the override brings
the shared ones back, and sharing a view's version makes it every view's.
Each zone keeps its own options, serial and file.

Linking existing zones changes no answer: what is the same everywhere
becomes shared, the rest stays local. Unlinking keeps every record, all
local. ACME challenges are written once per link, and --view all changes
a link once. jarl zone link/unlink, zone create --link-with, record
--local/--shared, LINK column, web UI controls, POST /zones/{zone}/link
and /unlink, validation checks linked_*, store migration 11, docs and
e2e.

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

internal/engine/inputs.go

@@ -55,6 +55,10 @@ const (
 	// back, become view.update or settings.update operations.
 	OpExposureAck   = "exposure.ack"
 	OpExposureUnack = "exposure.unack"
+	// Linked zones (docs/views.md#linked-zones): requests that expand
+	// into zone and record updates.
+	OpZoneLink   = "zone.link"
+	OpZoneUnlink = "zone.unlink"
 )
 
 // AckInput acknowledges (or un-acknowledges) an exposure finding of a view
@@ -131,6 +135,13 @@ type ZoneInput struct {
 	Comment      *string `json:"comment,omitempty"`
 	// Disabled keeps the zone in Jarl but out of named's configuration.
 	Disabled *bool `json:"disabled,omitempty"`
+	// LinkGroup is the zone's link group (0: not linked). Set by zone.link
+	// and zone.unlink; requests use those.
+	LinkGroup *int64 `json:"link_group,omitempty"`
+	// LinkWith (create only) links the new zone with the zone of the same
+	// name in this view, copying its shared records (or all of its
+	// records, when it isn't linked yet).
+	LinkWith string `json:"link_with,omitempty"`
 
 	// Create only: name servers for the apex NS records (default: the
 	// configured default name servers), additional records, and a zone to
@@ -167,6 +178,25 @@ type RecordInput struct {
 	PTR bool `json:"ptr,omitempty"`
 	// MissingOK makes a delete-by-match succeed when nothing matches.
 	MissingOK bool `json:"missing_ok,omitempty"`
+	// Local (requests, linked zones): true keeps the record in this view
+	// only (an override: the whole name and type becomes local here);
+	// false shares it with the linked zones. Unset: like the records of
+	// the same name and type, shared when there are none.
+	Local *bool `json:"local,omitempty"`
+	// SharedID (stored operations) ties the copies of a shared record
+	// together; 0 makes it local.
+	SharedID *int64 `json:"shared_id,omitempty"`
+}
+
+// LinkInput links zones of the same name in several views, or (unlink)
+// takes one out of its link.
+type LinkInput struct {
+	ZoneID int64  `json:"zone_id,omitempty"`
+	Zone   string `json:"zone,omitempty"`
+	View   string `json:"view,omitempty"`
+	// With are the views whose zone of the same name to link with (link
+	// only; default: every view that has one).
+	With []string `json:"with,omitempty"`
 }
 
 // RRSetInput replaces all records of one name and type.
@@ -181,6 +211,11 @@ type RRSetInput struct {
 	Comment *string           `json:"comment,omitempty"`
 	// NewIDs are allocated for records that need to be created.
 	NewIDs []int64 `json:"new_ids,omitempty"`
+	// Local (requests): like RecordInput.Local, for the whole set.
+	Local *bool `json:"local,omitempty"`
+	// Shared (stored operations, linked zones): the records are shared
+	// (true) or local (false).
+	Shared *bool `json:"shared,omitempty"`
 }
 
 // ViewInput creates or updates a view.