FEAT: Scan history browsing

[wakonig]

As a user analyzing data,
I want to browse previously acquired scans and add comments,
so that important observations, issues, or context are preserved alongside the data.

Acceptance criteria

• Users can browse scans by time, scan ID, scan number, deployment or pgroup
• Scan metadata is visible without loading full datasets
• Users can add, edit, and view comments
• Comments are stored persistently and linked to the scan