swarm-ui: the error and empty texts say agents and hives, not roster

The word named three different things. Only the four strings an operator reads change; code comments and names stay.

frontend/packages/swarm-ui/src/agent/detail/AgentDetailPopover.tsx

@@ -82,7 +82,7 @@ export function AgentDetailPopover({
           ) : row ? (
             <AgentDetail row={row} actions={actions} />
           ) : row === null ? (
-            <p>{agent} is not in the swarm's agent roster</p>
+            <p>{agent} is not in the swarm's agent list</p>
           ) : (
             <SkeletonLines label="the agent's details" count={4} />
           )}

frontend/packages/swarm-ui/src/pages/agents/AgentsPage.tsx

@@ -152,7 +152,7 @@ export function AgentsPage() {
       ) : null}
       {error ? (
         <ApiErrorPanel
-          context="failed to load the agent roster"
+          context="failed to load the agents"
           problem={error}
         />
       ) : null}

frontend/packages/swarm-ui/src/pages/swarm/HivesCard.tsx

@@ -135,7 +135,7 @@ function HiveRoster() {
       </DisclosureAction>
       {error ? (
         <ApiErrorPanel
-          context="failed to load the hive roster"
+          context="failed to load the hives"
           problem={error}
         />
       ) : null}
@@ -147,7 +147,7 @@ function HiveRoster() {
           columns={COLUMNS}
           rows={hives}
           rowKey={(h) => h.name}
-          emptyMessage="no hives in the roster yet"
+          emptyMessage="no hives yet"
           storageKey="swarm-ui:hives:table-filters"
         />
       ) : null}