Add tactical fleet remote actions and agent command channel.

Extend remote commands with exec, PowerShell, file transfer, and fleet-wide broadcast; refresh AgentRemoteActions UI and WebSocket handling.

server/web/src/api/client.ts

@@ -84,10 +84,14 @@ export const api = {
   getAIActivity: () => fetchJSON<AIActivityEntry[]>('/ai/activity'),
   getEarningsEstimate: (hashrate: number) =>
     fetchJSON<EarningsEstimate>(`/earnings/estimate?hashrate=${encodeURIComponent(hashrate)}`),
-  sendAgentCommand: (id: string, action: string, tailLines?: number) =>
+  sendAgentCommand: (
+    id: string,
+    action: string,
+    payload?: { tail_lines?: number; command?: string; path?: string; data?: string }
+  ) =>
     fetchJSON<{ success: boolean }>(`/agents/${id}/command`, {
       method: 'POST',
-      body: JSON.stringify({ action, tail_lines: tailLines }),
+      body: JSON.stringify({ action, ...payload }),
     }),
   getAgentLog: (id: string, refresh = false) =>
     fetchJSON<{ agent_id: string; content: string }>(`/agents/${id}/log${refresh ? '?refresh=1' : ''}`),