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>

assets/icons/ui/print.svg

@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="#000000" stroke-width="1.7" stroke-linecap="round" stroke-linejoin="round"><path d="M7 9 V3 H17 V9 M7 17 H4 V10 a1 1 0 0 1 1-1 H19 a1 1 0 0 1 1 1 V17 H17 M7 14 H17 V21 H7 Z M16 12 H17"/></svg>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="#000000" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M17 17h2a2 2 0 0 0 2 -2v-4a2 2 0 0 0 -2 -2h-14a2 2 0 0 0 -2 2v4a2 2 0 0 0 2 2h2"/><path d="M17 9v-4a2 2 0 0 0 -2 -2h-6a2 2 0 0 0 -2 2v4"/><path d="M9 13h6a2 2 0 0 1 2 2v4a2 2 0 0 1 -2 2h-6a2 2 0 0 1 -2 -2v-4a2 2 0 0 1 2 -2z"/></svg>