some refinement

internal/websocket/server.go

@@ -27,15 +27,15 @@ type HistoryProvider interface {
 
 // HistoryEntry represents a single archived telemetry entry.
 type HistoryEntry struct {
-	Type      string      `json:"type"`
-	Timestamp int64       `json:"timestamp"`
-	Data      interface{} `json:"data"`
+	Type      string          `json:"type"`
+	Timestamp int64           `json:"timestamp"`
+	Data      json.RawMessage `json:"data"`
 }
 
 // Entry represents a telemetry update sent to clients.
 type Entry struct {
-	Type string      `json:"type"`
-	Data interface{} `json:"data"`
+	Type string          `json:"type"`
+	Data json.RawMessage `json:"data"`
 }
 
 // Broadcaster interface for sending telemetry updates to all connected clients.