Match the featured cover buttons row to the reference theme: drop the
dedicated slide button, let the icon-only image picker select multiple
images into a slide cover (single pick stays an image cover), and align
the loaded-state visibility matrix.
TinyMCE's skin injects .mce-fullscreen { z-index: 100 } at editor init,
after core editor.css, so the fullscreen editor (toolbar at the viewport
top) lost to the fixed navbar (.nav-fixed .header, z-index 999). Restore
core's intended 100010 with an element+class selector that outranks the
skin regardless of injection order; it stays below the submit media
dialog (100080). Also remove the dead .mce-top-part.affix rules (no
AKSRT script drives them) and pin both in a contract test.
Featured video preview now renders a real DPlayer (video-url/video-pic)
like the reference theme instead of a static image, so the cover video
plays on the submit page. Top-right bar gains the video-cover button
shown only when a video cover is loaded; backend honors pic_id and no
longer deletes the thumbnail before cover validation. Drop dead i18n
keys and data-can-* attributes.
kate522