Review pass on the Lightwell redesign: layout, copy and behavior fixes

Dialog buttons are Cancel then the primary action at the bottom right, and each page has one primary
action. List pages no longer repeat their title. Dates have the month written out. Fields in a row
line up, hints sit under fields instead of inside labels, and long certificate errors are clamped.
Organizations show whether local access is on and name the action; setting a user's password uses a
dialog instead of a browser prompt. Server errors for sign-in and ranges are reworded with a next step,
and the stray scrollbar inside tables is gone.

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

resauth.go

@@ -54,10 +54,10 @@ func (s *Server) protectedMapping(id string) *model.Mapping {
 func checkReturn(m *model.Mapping, raw string) (*url.URL, error) {
 	u, err := url.Parse(raw)
 	if err != nil || (u.Scheme != "http" && u.Scheme != "https") || u.Host == "" {
-		return nil, errors.New("invalid return address")
+		return nil, errors.New("This sign-in link is incomplete. Open the page you wanted again and you will be brought back here.")
 	}
 	if (m.Proto == model.ProtoHTTPS) != (u.Scheme == "https") {
-		return nil, errors.New("return address uses the wrong scheme")
+		return nil, errors.New("This sign-in link is not valid. Open the page you wanted again and you will be brought back here.")
 	}
 	host := u.Hostname()
 	port := u.Port()
@@ -68,7 +68,7 @@ func checkReturn(m *model.Mapping, raw string) (*url.URL, error) {
 		}
 	}
 	if !model.HostMatches(m.Hostname, strings.ToLower(host)) || port != fmt.Sprint(m.Port) {
-		return nil, errors.New("return address doesn't belong to this resource")
+		return nil, errors.New("This sign-in link points somewhere else. Open the page you wanted again and you will be brought back here.")
 	}
 	return u, nil
 }