chore: gitignore local agent-tooling artifacts

Keep Codex / claude-flow scaffolding (.agents/, .codex/, AGENTS.md) out
of the repo — these are locally generated and not project sources.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitignore

@@ -30,3 +30,8 @@ solitaire_server/e2e/test-results/
 deploy/matomo-secret.yaml
 deploy/*-secret.yaml
 deploy/*-auth-secret.yaml
+
+# Local agent-tooling artifacts (Codex / claude-flow) — keep out of the repo
+/.agents/
+/.codex/
+/AGENTS.md