Replace reconnecting badge with pull-to-refresh

UX improvements:
- Remove misleading "Reconnecting..." badge overlay
- Implement native pull-to-refresh gesture on agent list
- Add manual refresh capability via pull gesture

Technical changes:
- Add refreshSession() method to session context
- Add refreshAll() to useAggregatedAgents hook
- Integrate RefreshControl in AgentList component
- Use isRevalidating state for refresh indicator
- Apply theme colors to RefreshControl for consistency

Benefits:
- Familiar iOS/Android UX pattern
- No UI overlays blocking content
- Clear user action (pull) → clear feedback (refresh)
- Accurate state representation (syncing vs reconnecting)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

packages/app/src/stores/session-store.ts

@@ -169,6 +169,7 @@ export interface SessionState {
     restartServer: (reason?: string) => void;
     initializeAgent: (params: { agentId: string; requestId?: string }) => void;
     refreshAgent: (params: { agentId: string; requestId?: string }) => void;
+    refreshSession: () => void;
     cancelAgentRun: (agentId: string) => void;
     sendAgentMessage: (
       agentId: string,