Ctrl/Cmd+F (and a toolbar button) opens a compact find bar over the
rendered Markdown preview, with match highlighting, a live count, and
next/previous navigation that scrolls the current match into view.
Escape closes the bar and returns focus where it was.
Merge follow-ups on top of the contribution: mount the bar in the
fullscreen viewer as well as the inline preview, combine it with the
FilePreviewCommentMenu wrapper that landed on main, debounce the
highlight pass so typing does not re-walk the whole document on every
keystroke, use the status-warning theme utilities instead of raw CSS
variables for the highlights, and add the Turkish strings for the
locale added after the branch was cut.
Closes#2401
Bohdan Triapitsyn
e47d87c3d6