HIFI cryomag temp scanner OPI

- Ensure all graph buffers are the same length
- Ensure all lines are set to trigger off `HEARTBEAT` or similar, not on pv change
- Can we make the button to open plots from the table view open a new opi/new tab by default

Locate the HIFI cryomag temperature scanner OPI and inspect its graph buffers, line-trigger behavior, and table-view plot button. Confirm the required behavior for equal-length buffers, HEARTBEAT-based triggering, and opening plots in a new OPI or tab; done means all three behaviors work consistently.

索引モデルが issue の本文から書いたものです。