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 <[email protected]>

assets/icons/ui/doc_new.svg

@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="#000000" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"><path d="M6 3 H14 L19 8 V21 H6 Z M14 3 V8 H19"/></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="M14 3v4a1 1 0 0 0 1 1h4"/><path d="M17 21h-10a2 2 0 0 1 -2 -2v-14a2 2 0 0 1 2 -2h7l5 5v11a2 2 0 0 1 -2 2z"/><path d="M12 11v6"/><path d="M9 14h6"/></svg>

assets/icons/ui/file_export.svg

@@ -0,0 +1 @@
+<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="M14 3v4a1 1 0 0 0 1 1h4"/><path d="M11.5 21h-4.5a2 2 0 0 1 -2 -2v-14a2 2 0 0 1 2 -2h7l5 5v5"/><path d="M13 19h7"/><path d="M17 16l3 3l-3 3"/></svg>

assets/icons/ui/folder_open.svg

@@ -0,0 +1 @@
+<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="M5 19l2.757 -7.351a1 1 0 0 1 .936 -.649h12.307a1 1 0 0 1 .986 1.164l-.996 5.211a2 2 0 0 1 -1.964 1.625h-14.03a2 2 0 0 1 -2 -2v-11a2 2 0 0 1 2 -2h4l3 3h7a2 2 0 0 1 2 2v2"/></svg>

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>

assets/icons/ui/save.svg

@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="#000000" stroke-width="1.8" stroke-linecap="round" stroke-linejoin="round"><path d="M4 4 H17 L20 7 V20 H4 Z M8 4 V9 H15 V4 M7 20 V14 H17 V20"/></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="M6 4h10l4 4v10a2 2 0 0 1 -2 2h-12a2 2 0 0 1 -2 -2v-12a2 2 0 0 1 2 -2"/><path d="M12 14m-2 0a2 2 0 1 0 4 0a2 2 0 1 0 -4 0"/><path d="M14 4v4h-6v-4"/></svg>