fix(canvas): skip /registry/:id/peers fetch when workspace not online

The peers endpoint requires a workspace-scoped bearer token (see
validateDiscoveryCaller in handlers/discovery.go — designed for
agent-to-agent calls). The canvas session doesn't hold that token, so
every Details-tab open for a provisioning / failed / offline workspace
fired a 401 that cluttered devtools and lit up the error banner even
though the real UX here is "no peers — the workspace hasn't booted."

Gate the fetch on status ∈ {online, degraded} and render an empty
Peers list for everything else.

Follow-up: give the canvas a way to see peers for any workspace (admin
session should be enough). Tracked separately — this fix just quiets
the noise on the common case.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

canvas/src/components/tabs/DetailsTab.tsx

@@ -58,8 +58,19 @@ export function DetailsTab({ workspaceId, data }: Props) {
   }, [workspaceId]);
 
   useEffect(() => {
+    // The /registry/:id/peers endpoint requires a workspace-scoped
+    // bearer token (validateDiscoveryCaller) which the canvas session
+    // doesn't hold. For a still-provisioning or failed workspace there
+    // are no peers to show anyway — skip the fetch so the Details tab
+    // doesn't flood devtools with 401 noise and so the empty Peers
+    // section renders cleanly.
+    if (data.status !== "online" && data.status !== "degraded") {
+      setPeers([]);
+      setPeersError(null);
+      return;
+    }
     loadPeers();
-  }, [loadPeers]);
+  }, [loadPeers, data.status]);
 
   const handleSave = async () => {
     setSaving(true);