feat(app): tappable fleet stat cards open a filtered agent list

The Running / Waiting / Done cards now navigate to a new agent-list
screen pre-filtered to that bucket, using exactly the same grouping as
the counts so the number tapped is the number listed. The list shows
every agent row the API knows — an agent that hasn't dropped a
checkmark yet is visible the moment it spawns, with a status badge, its
age, and a live last-output line while it works. Rows open the agent
detail screen, whose back button now returns to wherever the detail was
opened from (fleet or the list).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01731mKtVzsfeT4Vi3TvkR48

app/App.tsx

@@ -49,6 +49,7 @@ import { ClaudeLoginScreen } from "./src/screens/manage/ClaudeLoginScreen";
 import { ServerConfigProvider, useServerConfig } from "./src/state/ServerConfig";
 import { ConnectScreen } from "./src/screens/ConnectScreen";
 import { FleetScreen } from "./src/screens/FleetScreen";
+import { AgentListScreen } from "./src/screens/AgentListScreen";
 import { AgentDetailScreen } from "./src/screens/AgentDetailScreen";
 import { AnswerScreen } from "./src/screens/AnswerScreen";
 import { SpawnScreen } from "./src/screens/SpawnScreen";
@@ -63,6 +64,7 @@ function Router() {
   const screens: Record<ScreenName, () => React.JSX.Element> = {
     connect: ConnectScreen,
     fleet: FleetScreen,
+    agentList: AgentListScreen,
     detail: AgentDetailScreen,
     answer: AnswerScreen,
     spawn: SpawnScreen,