feat: synchronous replay endpoint with agent response status

Add dedicated POST /agents/{id}/replay endpoint that uses
addCommandWithReply to wait for the agent ACK (30s timeout).
Returns the actual replay result (status, message, data) instead
of just a delivery confirmation.

Frontend toast now reflects the agent's response: "Replay completed"
on success, agent error message on failure, timeout message if the
agent doesn't respond.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/security/SecurityConfig.java

@@ -72,6 +72,7 @@ public class SecurityConfig {
                         .requestMatchers(HttpMethod.POST, "/api/v1/agents/*/commands").hasAnyRole("OPERATOR", "ADMIN")
                         .requestMatchers(HttpMethod.POST, "/api/v1/agents/groups/*/commands").hasAnyRole("OPERATOR", "ADMIN")
                         .requestMatchers(HttpMethod.POST, "/api/v1/agents/commands").hasAnyRole("OPERATOR", "ADMIN")
+                        .requestMatchers(HttpMethod.POST, "/api/v1/agents/*/replay").hasAnyRole("OPERATOR", "ADMIN")
 
                         // Search endpoints
                         .requestMatchers(HttpMethod.GET, "/api/v1/search/**").hasAnyRole("VIEWER", "OPERATOR", "ADMIN", "AGENT")