✨ Add bep.JSON helper for JSON assertion in tests

- Create internal/testutil/bep package with JSON helper
- Use bep.JSON in formatters/json_test.go, models/entry_test.go, and models/meta_test.go

internal/testutil/bep/json.go

@@ -0,0 +1,21 @@
+package bep
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/nalgeon/be"
+)
+
+func JSON(t *testing.T, got, want []byte) {
+	t.Helper()
+
+	var gotAny, wantAny any
+	err := json.Unmarshal(want, &wantAny)
+	be.Err(t, err, nil)
+
+	err = json.Unmarshal(got, &gotAny)
+	be.Err(t, err, nil)
+
+	be.Equal(t, gotAny, wantAny)
+}