✨ Email CKEditor enhancements (and fixes)

Is your feature request related to a problem? Please describe.

It is - I'm thinking about switching to Nextcloud Mail, but currently, there's a big problem - why can't we align photos in the editor? And also, the editor is unusable in dark mode because of the colors (see below).

Describe the solution you'd like

Photo aligning

It needs fixes, like including an plug-in for the CKEditor for aligning photos/pictures. Currently, there is no way to align the photos for some reason. The editor now looks like this:

=> Unlike in CKEditor's demo, the toolbar for photos is missing.

Wrong colours in dark mode

The CKEditor used is unusable, when Nextcloud is set to dark mode. see below:

Describe alternatives you've considered

Using other email client, but none of them integrate into Nextcloud.

Additional context

I'm thinking about trying to fit this, but I'm not much experienced in Vue.js, so I'd love it, if anyone help out with this.
Thanks!

No files or tests are named; start by locating the Mail editor's CKEditor integration and its Vue.js configuration. Review how image controls and dark-mode colors are configured, then verify that image alignment is available and the editor remains usable in dark mode.