fix: WORKSPSACES section + remaining emoji icons replaced

- base.html: séparateur entre version et Log out, _local_workspaces_for_user
- board.py: _local_workspaces_for_user helper, app_version, fix emoji icons
- dashboard.py: _local_workspaces_for_user helper
- library.html: 📚📁📄🕒⭐👥🌐🔒📦 → SVG + icon map
- workspaces.html: 📁🔍🗑📝 → SVG
- local_workspace.html: page_icon, empty states, icon functions → SVG
- settings.html: 👤🔔 → SVG nav icons
- _icons.html: +'bell' icon
- CSS: .nav-icon-inline, .empty-state-icon
- 143 tests passent

static/css/app.css

@@ -524,6 +524,9 @@ input, select, textarea { font-family: inherit; color: inherit; }
 .page-icon-svg svg {
   vertical-align: middle;
 }
+.nav-icon-inline { margin-right: 6px; vertical-align: middle; display: inline-flex; align-items: center; }
+.nav-icon-inline svg { vertical-align: middle; }
+.empty-state-icon { display: inline-flex; align-items: center; justify-content: center; margin-bottom: 12px; }
 
 .sidebar-item:active .page-icon {
   cursor: grabbing;