feat: show who an Azure account signs in as, in Details on its row

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

internal/provider/azure/accounts.go

@@ -94,6 +94,15 @@ func readAccounts(path string) ([]account, error) {
 			a.anchor, a.anchorEnabled = s.ID, enabled
 		}
 	}
+	// az leaves the tenant's name out of some entries: take it from
+	// another in the same tenant.
+	for i := range out {
+		for _, b := range out {
+			if out[i].tenantName == "" && b.tenant == out[i].tenant {
+				out[i].tenantName = b.tenantName
+			}
+		}
+	}
 	slices.SortStableFunc(out, func(a, b account) int {
 		if a.isDefault != b.isDefault {
 			if a.isDefault {