Describe the agents panel's limit rows and sign-in link as they are (#14430)

The manual still said the panel shows the percentage used and that an idle
account keeps its last known limits, and the README that sign-in trouble is
only text. Rows show the time to reset with the percentage on hover, and a
lapsed sign-in is a Sign-in required link that signs the account in again.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

shell/plugins/agents/README.md

@@ -19,8 +19,9 @@ Every subscription on one page, limits first.
   per limit window: its meter and the time until it resets (the exact percentage
   on hover). A model-scoped allowance on the same clock (Claude's Fable weekly
   limit) is a tick on that window's meter rather than a line of its own; the
-  row's tooltip names it. Sign-in and endpoint trouble shows under the name in the urgent
-  color. Limits kept from an earlier check after a failed one dim, and their
+  row's tooltip names it. A lapsed or missing sign-in shows a _Sign-in required_ link that signs
+  that account in again from the panel; other endpoint trouble shows under the
+  name in the urgent color. Limits kept from an earlier check after a failed one dim, and their
   tooltip says how old they are.
 - **Accounts** — an agent with more than one subscription account (see
   `omarchy agent account`) lists each: name and plan on one line (the email on hover), and its own limit