M7: recent files as thumbnail cards on the home screen (#249)

The Recents section shows recent files as cards: the picture each file
carries (thumbnail.png in .figcraft and .fig, an image file itself) fitted
on its first page's colour, a divider, and a footer with the file's icon,
name and "Edited ... ago" (or "File not found"); the full path on hover.
Pictures are read off the frame's thread, only for cards in view, cached
by path and modification time, capped in bytes and pixels; missing,
damaged or oversized ones give a placeholder. They fade in, and cards
show a skeleton until their file has been looked at.

A sort menu (Alphabetical, Date created, Last modified; either order) and
a grid/list toggle sit above them. The list is a Name, Last modified and
Created table whose headers sort. View (per section) and sort are kept in
the preferences and set with ui.set {homeRecentsView, homeRecentsSort,
homeRecentsOrder}. A click selects, a double-click or Enter opens, arrow
keys move the selection; a right-click offers Open, Show in folder and
Remove from recents (file.openRecent {remove}).

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: bflatastic <bombayapirat@gmail.com>

crates/engine/src/cmd/file.rs

@@ -37,7 +37,7 @@ pub fn specs() -> Vec<CommandSpec> {
         spec!(
             "file.openRecent",
             "Open recent",
-            "{path? | index? (into the list), clear? (forget them all)}  opens a recent file; a file that no longer exists is dropped from the list. Returns the list, newest first: {files: [{path, name, exists}]} (opening returns what `file.open` does)",
+            "{path? | index? (into the list), clear? (forget them all), remove? (a path: forget that one)}  opens a recent file; a file that no longer exists is dropped from the list. Returns the list, newest first: {files: [{path, name, exists}]} (opening returns what `file.open` does)",
             false,
             open_recent
         ),
@@ -625,6 +625,9 @@ fn open_recent(s: &mut Session, p: &Value) -> Result<Value> {
     if p.get("clear").and_then(Value::as_bool) == Some(true) {
         s.prefs.recent_files.clear();
     }
+    if let Some(gone) = string(p, "remove") {
+        s.prefs.recent_files.retain(|r| *r != gone);
+    }
     let path = match (string(p, "path"), num(p, "index")) {
         (Some(path), _) => Some(path),
         (None, Some(i)) => Some(s.prefs.recent_files.get(i.max(0.0) as usize).cloned().ok_or_else(|| bad(CMD, "no such recent file"))?),