dashboard: a token handed over to another member's dashboard

Opening another member's dashboard passes a token reading only, for
five minutes, in the URL's fragment; its login page begins a session
with it. Tokens may be asked for with a shorter lifetime.

Auth plan M3 (hand-off).

1 files changed, 4 insertions, 2 deletions

diff --git a/docs/dashboard.md b/docs/dashboard.md
index 271592a..322abc6 100644
--- a/docs/dashboard.md
+++ b/docs/dashboard.md
@@ -200,8 +200,10 @@ measured.
 * **Right-click a node**: its menu: subscribing, and opening its dashboard.
 * **Open a node's dashboard** (its menu): in this page, where the node publishes one
   (`--dashboard-url`, in the member list; e.g. behind a reverse proxy,
-  [`operations.md`](operations.md)). The other dashboard asks for its own credentials
-  where its proxy or node does. It opens as this one was left: the map's nodes where
+  [`operations.md`](operations.md)). A token from this node goes along, reading only,
+  for five minutes: where the browser has no session at the other dashboard, its login
+  page begins one with it (reading only; log in there to do more), unless its proxy asks
+  for credentials of its own. It opens as this one was left: the map's nodes where
   they were (on a dynamic map they then move to their places among the other node's
   links, smoothly; new ones are placed among them), the view, the pins, what is in
   focus, the legend shown or hidden, what is open in the figures and in the document,