feat(ui): replace app-menu logo with a quick-access file toolbar

Remove the OCS-logo button and the dropdown menu it opened; the top strip
now shows direct New / Open / Save / Save As / Print buttons ahead of the
undo/redo controls. Drop the HELP and OPTIONS commands (HELP dumped text to
the command line, OPTIONS aliased the drafting-settings popup).

The app-menu overlay is gone, so its rendering code, MENU_ITEMS, four dead
messages, and the LOGO_RED / GEAR / HELP assets are removed. The recents
list it held is the only survivor — moved into OpenCADStudio.recent_files
via a new app/recent.rs, backing the Start page's Recent Documents panel.

Quick-access icons are redrawn in a cleaner style (file-plus, folder-open,
device-floppy, file-export, printer) and tinted light so they read on the
dark strip; FOLDER / DOC keep their old glyphs for the file browser.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/update/file.rs

@@ -240,7 +240,7 @@ pub(super) fn on_open_file(&mut self) -> Task<Message> {
                         caches.corrupt_dropped
                     ));
                 }
-                self.app_menu.push_recent(path.clone());
+                self.push_recent(path.clone());
 
                 let current_is_empty = {
                     let t = &self.tabs[self.active_tab];