feat: add supervisor prototype with embedded frontend

internal/domain/agent.go

@@ -0,0 +1,10 @@
+package domain
+
+import "time"
+
+type Agent struct {
+	ID        string    `json:"id"`
+	Name      string    `json:"name"`
+	Kind      string    `json:"kind"`
+	CreatedAt time.Time `json:"createdAt"`
+}