1. add/improve comments to help future readers could understand the
problem more easily.
2. add an error log to LDAP with username fallback
3. use `or` instead of `Iif` for "repo/branch_dropdown" (`Iif` was a
mistake, but it doesn't really affect the UI)
4. add `tw-font-mono` style to container digest to match dockerhub
5. fix a bug in RepoBranchTagSelector: the form is not updated when
there is no click to an item
---------
Co-authored-by: delvh <dev.lh@web.de>
