AI modified/generated indicator in file rights - #2478

The official icons must not be restyled by themes, so they are not
registered as theme icons. Their view boxes are cropped to the mark,
which leaves the space around it to stylesheets instead of the clear
space that differs per icon. The letter color is exposed as custom
property since the badge follows the surrounding text color. Since
the icons render the wording as graphic, they carry the translated
label as alt text.

Items combine label, rights, license and AI indicator, so that the
widgets do not have to lay out both kinds of information themselves.
Data attributes mark which items carry rights, where labels are and
which parts an item consists of, since widget stylesheets cannot
address the hashed class names of another CSS module. Laying out the
parts as wrapping flex items makes narrow columns break between them
instead of separating an icon from the text that explains it, and
leaves no indent in front of a part that moved to its own line.

Both icons share one button so that they appear as one marker and the
tooltip covers rights and AI information alike. The copyright icon
comes last to stay aligned with the tooltip arrow. Only the basic AI
symbol is used since the tooltip spells out the wording. Keeping
items from wrapping only inside their parts lets rights and AI
information sit side by side or stack, and leaves the scroller for
parts that are too wide on their own. Since only the button follows
the surrounding text color, the letters of the marks are inverted
there alone: the tooltip is dark in any case.

The copyright sign now only precedes items that actually carry rights
and belongs to that part, so it stays with the rights when the AI
indicator moves to its own line. Addressing the label via data
attribute keeps the rule that hides it for single items independent
of which other elements an item contains.

Content elements opt in per element, so that a representative subset
renders the indicators. Each of them gets its own story next to the
one without indicators to keep both cases covered. The kind of
indicator differs per file collection, which puts both pills next to
each other in stories of elements that combine a media file with a
poster image.