feat: outline SVG icons + version + workspaces in user menu

- _icons.html: 25 outline SVG icons (Feather/Lucide style, stroke=currentColor)
- base.html: toutes les icônes emoji remplacées par {{ fd_icon() }}
  - Sidebar sections, empty states, user menu, footer links, context menu
  - JS getSvgIcon() helper pour rendu dynamique
- User menu: ajout version (FlowDeck v4.0.3) + liste workspaces locaux
  - Entre Switch workspace et Log out, avec ✓ sur le workspace actif
- dashboard.py: _sidebar_data enrichi (app_version, local_workspaces)
- CSS: .page-icon-svg, .um-version, .um-section-label, .um-item svg
- Dark + light theme compatible (stroke:currentColor)
- 143 tests passent

static/css/app.css

@@ -278,9 +278,12 @@ input, select, textarea { font-family: inherit; color: inherit; }
   padding: 7px 14px; font-size: 13px; color: var(--text);
   text-decoration: none; cursor: pointer; transition: background 100ms;
 }
+.um-item svg { flex-shrink: 0; }
 .um-item:hover { background: var(--bg-hover); }
 .um-danger { color: var(--danger); }
 .um-danger:hover { background: rgba(255,80,80,.1); }
+.um-version { font-size: 11px; color: var(--text-dim); padding: 4px 14px 2px; }
+.um-section-label { font-size: 11px; color: var(--text-dim); text-transform: uppercase; letter-spacing: .5px; padding: 4px 14px 2px; }
 
 .sidebar-actions {
   display: flex;
@@ -510,6 +513,18 @@ input, select, textarea { font-family: inherit; color: inherit; }
   cursor: grab;
 }
 
+/* Outline SVG icons (from _icons.html / getSvgIcon) */
+.page-icon-svg {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 18px;
+  flex-shrink: 0;
+}
+.page-icon-svg svg {
+  vertical-align: middle;
+}
+
 .sidebar-item:active .page-icon {
   cursor: grabbing;
 }