feat(proto): SyncMonitors + ReportChecks RPCs

proto/vantage/v1/vantage.proto

@@ -10,6 +10,8 @@ service Vantage {
   rpc UploadGeneratedKey(UploadKeyRequest)      returns (UploadKeyResponse);
   rpc ReportUpdates(ReportUpdatesRequest)       returns (ReportUpdatesResponse);
   rpc ReportInventory(InventoryReport)          returns (InventoryReportResponse);
+  rpc SyncMonitors(SyncMonitorsRequest)         returns (SyncMonitorsResponse);
+  rpc ReportChecks(ReportChecksRequest)         returns (ReportChecksResponse);
   // Bidirectional stream: agent sends auth once, server pushes commands.
   rpc CommandStream(stream AgentMessage)        returns (stream ServerCommand);
 }
@@ -117,6 +119,45 @@ message InventoryReport {
 
 message InventoryReportResponse {}
 
+message MonitorSpec {
+  string monitor_id      = 1;
+  string type            = 2;
+  string url             = 3;
+  string host            = 4;
+  int32  port            = 5;
+  string method          = 6;
+  int32  expected_status = 7;
+  string keyword         = 8;
+  int32  tls_warn_days   = 9;
+  int32  interval_sec    = 10;
+  int32  retries         = 11;
+}
+
+message SyncMonitorsRequest {
+  string server_id   = 1;
+  string agent_token = 2;
+}
+
+message SyncMonitorsResponse {
+  repeated MonitorSpec monitors = 1;
+}
+
+message CheckResult {
+  string monitor_id       = 1;
+  bool   up               = 2;
+  int32  latency_ms       = 3;
+  string message          = 4;
+  int64  cert_expiry_unix = 5;
+}
+
+message ReportChecksRequest {
+  string server_id   = 1;
+  string agent_token = 2;
+  repeated CheckResult results = 3;
+}
+
+message ReportChecksResponse {}
+
 message ApplyUpdatesCmd {}
 
 message ServerCommand {