feat(observabilidade): systemd timer diário import worklog

- Service oneshot invoca sessions-worklog-import.ts --discussion all --since-days 7
- Timer OnCalendar=*-*-* 03:00:00 com Persistent=true (catch-up)
- EnvironmentFile reutiliza observabilidade-patterns.env (MCP_GATEWAY_TOKEN)
- Logs append em ~/.claude-work/observabilidade-worklog-import.log

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

systemd/observabilidade-worklog-import.timer

@@ -0,0 +1,10 @@
+[Unit]
+Description=Observabilidade — import diário de worklogs Desk
+
+[Timer]
+OnCalendar=daily
+OnCalendar=*-*-* 03:00:00
+Persistent=true
+
+[Install]
+WantedBy=default.target