SQUAC alert emails: less precision/more readability on channel descriptions

SQUAC alert emails list breaching channels with too many decimals, which makes them hard to read. Round to some significant figures (can't just do tenth of a second because metrics have different ranges).

Example of undesired behavior:
<img width="664" height="782" alt="Image" src="https://github.com/user-attachments/assets/31f86f20-c081-443d-9a84-960ca997d7e2" />