feat(dashboard): resize souris, DnD live, panel widgets, icônes corrigées

- Resize widget via drag sur le coin bas-droit (mousedown → mousemove →
  snap à taille 1 ou 2 colonnes selon distance)
- DnD live : les autres widgets se déplacent pendant le drag (onDragEnter
  réordonne le tableau + onDragEnd restaure si annulé)
- Mode édition : panel latéral avec tous les widgets (œil toggle visible/masqué),
  survol d'une entrée met en avant (outline) le widget correspondant dans la grille
- Bouton mode édition : icône seule (lnid-pencil-1)
- Correction noms d'icônes LineIcons (lnid-pencil-1, lnid-eye, lnid-eye-closed,
  lnid-cross → supprimé en faveur de toggles dans le panel)
- Suppression des classes CSS obsolètes (edit-mode-banner, widget-add-btn, etc.)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/css/pages.css

@@ -552,53 +552,91 @@
 .widget-size-2 { grid-column: span 2; }
 @media (max-width: 720px) { .widget-size-2 { grid-column: span 1; } }
 
+.widget { position: relative; }
 .widget.is-dragging { opacity: 0.35; transform: scale(.97); }
-.widget.drag-over   { outline: 2px dashed var(--neu-primary); transform: scale(1.02); }
+.widget-highlighted { outline: 2px solid var(--neu-primary) !important; outline-offset: 2px; }
 
-.widget-edit-bar {
+/* Edit mode layout : grid + panel côte à côte */
+.edit-mode-layout {
   display: flex;
-  align-items: center;
-  gap: .375rem;
-  padding: .25rem 0 .75rem;
-  border-bottom: 1px solid var(--neu-border);
-  margin-bottom: .75rem;
+  gap: 1.25rem;
+  align-items: flex-start;
+}
+.edit-mode-layout .widgets-grid {
+  flex: 1;
+  min-width: 0;
 }
-.widget-edit-bar-title { flex: 1; font-size: .75rem; font-weight: 600; color: var(--neu-text-muted); text-transform: uppercase; }
 
-.edit-mode-banner {
-  display: flex;
-  align-items: center;
-  gap: .75rem;
-  padding: .625rem 1rem;
-  border-radius: var(--neu-radius-sm);
-  background: rgba(108, 142, 244, 0.1);
-  border: 1px solid var(--neu-primary);
-  margin-bottom: 1.25rem;
-  font-size: .875rem;
-  color: var(--neu-primary);
+/* Widget panel (liste de tous les widgets en mode édition) */
+.widget-panel {
+  width: 200px;
+  flex-shrink: 0;
+  position: sticky;
+  top: 1rem;
+  padding: 1rem;
 }
-.edit-mode-banner i { font-size: 1.1rem; }
-
-.widget-add-grid {
-  display: flex;
-  flex-wrap: wrap;
-  gap: .75rem;
-  margin-top: 1.5rem;
-}
-.widget-add-btn {
+.widget-panel-title {
   display: flex;
   align-items: center;
   gap: .5rem;
-  padding: .5rem 1rem;
-  border-radius: var(--neu-radius-sm);
-  border: 1px dashed var(--neu-border);
-  background: transparent;
-  color: var(--neu-text-muted);
-  cursor: pointer;
   font-size: .875rem;
-  transition: all .15s;
+  font-weight: 700;
+  margin: 0 0 .75rem 0;
+  padding-bottom: .5rem;
+  border-bottom: 1px solid var(--neu-border);
+}
+.widget-panel-list {
+  list-style: none;
+  padding: 0;
+  margin: 0;
+  display: flex;
+  flex-direction: column;
+  gap: .2rem;
+}
+.widget-panel-item {
+  display: flex;
+  align-items: center;
+  gap: .5rem;
+  padding: .4rem .375rem;
+  border-radius: var(--neu-radius-sm);
+  cursor: default;
+  transition: background .15s;
+}
+.widget-panel-item:hover { background: rgba(108, 142, 244, 0.08); }
+.widget-panel-label {
+  flex: 1;
+  font-size: .85rem;
+  color: var(--neu-text-muted);
+  transition: color .15s;
+}
+.widget-panel-item.is-visible .widget-panel-label { color: var(--neu-text); }
+.widget-panel-toggle {
+  background: none;
+  border: none;
+  cursor: pointer;
+  color: var(--neu-text-muted);
+  padding: .2rem;
+  border-radius: .2rem;
+  line-height: 1;
+  transition: color .15s;
+}
+.widget-panel-toggle:hover { color: var(--neu-primary); }
+
+/* Resize handle (coin bas-droit de la tuile, edit mode) */
+.widget-resize-handle {
+  position: absolute;
+  bottom: 0;
+  right: 0;
+  width: 22px;
+  height: 22px;
+  cursor: ew-resize;
+  border-radius: 0 0 var(--neu-radius-sm) 0;
+  background: linear-gradient(135deg, transparent 50%, var(--neu-border) 50%);
+  transition: background .15s;
+}
+.widget-resize-handle:hover {
+  background: linear-gradient(135deg, transparent 50%, var(--neu-primary) 50%);
 }
-.widget-add-btn:hover { border-color: var(--neu-primary); color: var(--neu-primary); }
 
 /* ── Profil / préférences ────────────────────────────────────────────────────── */
 .settings-section {