feat(windows): add recoverable existing-agent credential upgrade

backend/app/frontend/agent_management_view.py

@@ -74,7 +74,7 @@ def agent_management_content(can_manage_agents: bool) -> str:
                 </h3>
             </div>
 
-            <p>
+            <p id="agentEnrollmentResultCopy">
                 This token is displayed only for this enrollment step.
                 Keep it private. MinerOps does not store the plaintext token.
             </p>
@@ -152,7 +152,9 @@ def agent_management_content(can_manage_agents: bool) -> str:
     </button>
 </div>
 
-<div id="agentManagementContent" hidden>
+<div id="agentManagementContent"
+    data-can-manage-agents="{str(can_manage_agents).lower()}"
+    hidden>
     <section class="agent-summary-grid" aria-label="Agent Management summary">
         <div class="panel agent-summary-card">
             <span>Registered Agents</span>
@@ -197,6 +199,7 @@ def agent_management_content(can_manage_agents: bool) -> str:
                             <th>Last check-in</th>
                             <th>Credential</th>
                             <th>Routing</th>
+                            <th>Action</th>
                         </tr>
                     </thead>
                     <tbody id="agentRows"></tbody>