feat: add host restart detection and fix agent version display

Potential fixes for issues #4 and #6.

Agent version display:
- Set CurrentVersion during registration instead of waiting for first check-in
- Update UI to show "Initial Registration" instead of "Unknown"

Host restart detection:
- Added reboot_required, last_reboot_at, reboot_reason fields to agents table
- Agent now detects pending reboots (Debian/Ubuntu via /var/run/reboot-required, RHEL/Fedora via needs-restarting)
- New reboot command type with 1-minute grace period
- UI shows restart alerts and adds restart button in quick actions
- Restart indicator badge in agent list

The reboot detection runs during system info collection and gets reported back to the server automatically.

Using shutdown command for now until we make the restart mechanism user-adjustable later - need to think on that.
Also need to come up with a Windows derivative outside of reading event log for detecting reboots.

aggregator-web/src/lib/api.ts

@@ -97,6 +97,14 @@ export const agentApi = {
     return response.data;
   },
 
+  // Trigger agent reboot
+  rebootAgent: async (id: string, delayMinutes: number = 1, message?: string): Promise<void> => {
+    await api.post(`/agents/${id}/reboot`, {
+      delay_minutes: delayMinutes,
+      message: message || 'System reboot requested by RedFlag'
+    });
+  },
+
   // Unregister/remove agent
   unregisterAgent: async (id: string): Promise<void> => {
     await api.delete(`/agents/${id}`);

aggregator-web/src/pages/Agents.tsx

@@ -21,6 +21,7 @@ import {
   CheckCircle,
   AlertCircle,
   XCircle,
+  Power,
 } from 'lucide-react';
 import { useAgents, useAgent, useScanAgent, useScanMultipleAgents, useUnregisterAgent } from '@/hooks/useAgents';
 import { useActiveCommands, useCancelCommand } from '@/hooks/useCommands';
@@ -298,6 +299,22 @@ const Agents: React.FC = () => {
     }
   };
 
+  // Handle agent reboot
+  const handleRebootAgent = async (agentId: string, hostname: string) => {
+    if (!window.confirm(
+      `Schedule a system restart for agent "${hostname}"?\n\nThe system will restart in 1 minute. Any unsaved work may be lost.`
+    )) {
+      return;
+    }
+
+    try {
+      await agentApi.rebootAgent(agentId);
+      toast.success(`Restart command sent to "${hostname}". System will restart in 1 minute.`);
+    } catch (error: any) {
+      toast.error(error.message || `Failed to send restart command to "${hostname}"`);
+    }
+  };
+
   // Handle agent removal
   const handleRemoveAgent = async (agentId: string, hostname: string) => {
     if (!window.confirm(
@@ -445,7 +462,7 @@ const Agents: React.FC = () => {
                   <span className="text-gray-500">Version:</span>
                   <div className="flex items-center space-x-1">
                     <span className="font-medium text-gray-900">
-                      {selectedAgent.current_version || 'Unknown'}
+                      {selectedAgent.current_version || 'Initial Registration'}
                     </span>
                     {selectedAgent.update_available === true && (
                       <span className="flex items-center text-xs text-amber-600 bg-amber-50 px-2 py-0.5 rounded-full">
@@ -485,6 +502,26 @@ const Agents: React.FC = () => {
           </div>
         </div>
 
+        {/* Restart Required Alert */}
+        {selectedAgent.reboot_required && (
+          <div className="mb-6 bg-amber-50 border border-amber-200 rounded-lg p-4">
+            <div className="flex items-start">
+              <AlertCircle className="h-5 w-5 text-amber-600 mt-0.5 mr-3 flex-shrink-0" />
+              <div className="flex-1">
+                <h3 className="text-sm font-medium text-amber-900">System Restart Required</h3>
+                <p className="text-sm text-amber-700 mt-1">
+                  {selectedAgent.reboot_reason || 'This system requires a restart to complete updates.'}
+                </p>
+                {selectedAgent.last_reboot_at && (
+                  <p className="text-xs text-amber-600 mt-1">
+                    Last reboot: {formatRelativeTime(selectedAgent.last_reboot_at)}
+                  </p>
+                )}
+              </div>
+            </div>
+          </div>
+        )}
+
         {/* Tabs */}
         <div className="mb-6">
           <div className="border-b border-gray-200">
@@ -947,6 +984,14 @@ const Agents: React.FC = () => {
                   </div>
                 </div>
 
+                <button
+                  onClick={() => handleRebootAgent(selectedAgent.id, selectedAgent.hostname)}
+                  className="w-full btn btn-warning"
+                >
+                  <Power className="h-4 w-4 mr-2" />
+                  Restart Host
+                </button>
+
                 <button
                   onClick={() => handleRemoveAgent(selectedAgent.id, selectedAgent.hostname)}
                   disabled={unregisterAgentMutation.isPending}
@@ -1157,14 +1202,22 @@ const Agents: React.FC = () => {
                       </div>
                     </td>
                     <td className="table-cell">
-                      <span className={cn('badge', getStatusColor(isOnline(agent.last_seen) ? 'online' : 'offline'))}>
-                        {isOnline(agent.last_seen) ? 'Online' : 'Offline'}
-                      </span>
+                      <div className="flex flex-col space-y-1">
+                        <span className={cn('badge', getStatusColor(isOnline(agent.last_seen) ? 'online' : 'offline'))}>
+                          {isOnline(agent.last_seen) ? 'Online' : 'Offline'}
+                        </span>
+                        {agent.reboot_required && (
+                          <span className="flex items-center text-xs text-amber-700 bg-amber-50 px-1.5 py-0.5 rounded-full w-fit">
+                            <Power className="h-3 w-3 mr-1" />
+                            Restart
+                          </span>
+                        )}
+                      </div>
                     </td>
                     <td className="table-cell">
                       <div className="flex items-center space-x-2">
                         <span className="text-sm text-gray-900">
-                          {agent.current_version || 'Unknown'}
+                          {agent.current_version || 'Initial Registration'}
                         </span>
                         {agent.update_available === true && (
                           <span className="flex items-center text-xs text-amber-600 bg-amber-50 px-1.5 py-0.5 rounded-full">

aggregator-web/src/types/index.ts

@@ -21,6 +21,10 @@ export interface Agent {
   status: 'online' | 'offline';
   created_at: string;
   updated_at: string;
+  current_version?: string;
+  reboot_required?: boolean;
+  last_reboot_at?: string | null;
+  reboot_reason?: string;
   metadata?: Record<string, any>;
   // Note: ip_address not available from API yet
 }