feat: restore agent capabilities from heartbeat after server restart

The heartbeat now carries capabilities (per protocol v2 update).
On each heartbeat, capabilities are updated in the agent registry.
On auto-heal (server restart), capabilities from the heartbeat
are used instead of empty Map.of(), so the agent's feature flags
(replay, routeControl, logForwarding, etc.) are restored
immediately on the first heartbeat.

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

cameleer3-server-app/src/main/java/com/cameleer3/server/app/controller/AgentRegistrationController.java

@@ -201,15 +201,17 @@ public class AgentRegistrationController {
     public ResponseEntity<Void> heartbeat(@PathVariable String id,
                                            @RequestBody(required = false) HeartbeatRequest request,
                                            HttpServletRequest httpRequest) {
-        boolean found = registryService.heartbeat(id);
+        Map<String, Object> capabilities = request != null ? request.getCapabilities() : null;
+        boolean found = registryService.heartbeat(id, capabilities);
         if (!found) {
             // Auto-heal: re-register agent from JWT claims after server restart
             var jwtResult = (JwtService.JwtValidationResult) httpRequest.getAttribute(
                     JwtAuthenticationFilter.JWT_RESULT_ATTR);
             if (jwtResult != null) {
                 String application = jwtResult.application() != null ? jwtResult.application() : "default";
+                Map<String, Object> caps = capabilities != null ? capabilities : Map.of();
                 registryService.register(id, id, application, "unknown",
-                        List.of(), Map.of());
+                        List.of(), caps);
                 registryService.heartbeat(id);
                 log.info("Auto-registered agent {} (app={}) from heartbeat after server restart", id, application);
             } else {