chore: traffic data 2026-06-21

Author: github-actions[bot]

traffic/stats-history.ndjson

@@ -63,3 +63,4 @@
 {"date": "2026-06-18", "stars": 415, "forks": 135, "watchers": 5, "open_issues": 1}
 {"date": "2026-06-19", "stars": 415, "forks": 135, "watchers": 5, "open_issues": 6}
 {"date": "2026-06-20", "stars": 415, "forks": 135, "watchers": 5, "open_issues": 6}
+{"date": "2026-06-21", "stars": 414, "forks": 135, "watchers": 5, "open_issues": 5}