Hold a found directory, a found service's unit, a container that would mount found data, and a step run in a held container on an adopted node (hq ADR 0103)

internal/store/store.go

@@ -115,8 +115,10 @@ type FoundFirewall struct {
 	FoundAt        time.Time `json:"found_at"`
 }
 
-// Held is one file or container found on an adopted node — present at a declared path or name,
-// with no record of this host having made it — and kept as it was found.
+// Held is one thing found on an adopted node — a file, directory or container present at a declared
+// path or name, or a service's unit, with no record of this host having made it — kept as it was
+// found; or what would reach one: a container mounting found data, an action run in a held
+// container (novox/hq ADR 0100, ADR 0103).
 type Held struct {
 	ID     string `json:"id"`
 	Module string `json:"module"`
@@ -133,10 +135,15 @@ type Held struct {
 	Owner  string `json:"owner,omitempty"`
 	Kept   string `json:"kept,omitempty"`
 
-	// A container's id as found, and whether it was running.
+	// A container's id as found, and whether it was running — or a service's unit, whether it
+	// was running.
 	Container string `json:"container,omitempty"`
 	Running   bool   `json:"running,omitempty"`
 
+	// Why says what was found when it is not the resource's own target: the path or volume a
+	// container would mount, or the held container an action would run in (novox/hq ADR 0103).
+	Why string `json:"why,omitempty"`
+
 	// Changed is what something other than the mesh has done to it since it was found —
 	// rewritten, stopped, replaced or gone — and empty while it is as found. Reported, never
 	// reverted: that is how a predecessor still writing is caught.