panel: scope the send log to a domain admin's own domains

The Deliveries list narrowed the journal only when exactly one domain was assigned, so an administrator with none or with two or more read every domain's rows. The domain scope is now an IN constraint the store query carries, a filter that states no scope matches nothing, and the domain/app query parameters are validated against the principal before the query runs.

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

internal/store/sendlog.go

@@ -178,15 +178,29 @@ func (s *Store) GetSendLog(id int64) (SendLogRow, error) {
 	return row, nil
 }
 
-// SendLogFilter narrows QuerySendLog/CountSendLog by domain and/or
-// application login. An empty field matches everything.
+// SendLogFilter narrows QuerySendLog/CountSendLog. It carries two kinds of
+// narrowing, and they behave in opposite ways on purpose.
+//
+// Domain and AppLogin are the operator's own filters, chosen in the UI: an
+// empty field matches everything.
+//
+// Domains and AllDomains are the authorization scope, which no query parameter
+// may widen. Domains is the exhaustive set of domain names the caller is
+// entitled to read, applied as an IN constraint; AllDomains lifts that
+// restriction and is the only way to read the whole journal. A zero-valued
+// filter therefore matches *no* rows: a caller that forgets to state a scope
+// gets an empty log rather than every tenant's mail, which is the failure mode
+// this struct exists to make impossible.
 type SendLogFilter struct {
-	Domain   string
-	AppLogin string
+	Domain     string
+	AppLogin   string
+	Domains    []string
+	AllDomains bool
 }
 
 // QuerySendLog returns send-log rows matching filter, newest first, for the
 // monitoring screen's server-side pagination (product.md's send-log view).
+// The filter's authorization scope is mandatory: see SendLogFilter.
 func (s *Store) QuerySendLog(filter SendLogFilter, limit, offset int) ([]SendLogRow, error) {
 	where, args := sendLogWhere(filter)
 	args = append(args, limit, offset)
@@ -233,6 +247,20 @@ func (s *Store) CountSendLog(filter SendLogFilter) (int64, error) {
 func sendLogWhere(f SendLogFilter) (string, []any) {
 	var clauses []string
 	var args []any
+	if !f.AllDomains {
+		// No scope is not "no restriction": a domain administrator whose last
+		// assignment was deleted owns nothing in the journal and must see
+		// nothing, and the same clause catches a caller that never set a scope.
+		if len(f.Domains) == 0 {
+			return " WHERE 1 = 0", nil
+		}
+		marks := make([]string, len(f.Domains))
+		for i, name := range f.Domains {
+			marks[i] = "?"
+			args = append(args, name)
+		}
+		clauses = append(clauses, "domain IN ("+strings.Join(marks, ", ")+")")
+	}
 	if f.Domain != "" {
 		clauses = append(clauses, "domain = ?")
 		args = append(args, f.Domain)