feat: page Routing complète + gestion server_audio_users dans Config

- Page Routing : matrices Entrées→Groupes et Groupes→Sorties avec checkboxes,
  éditeur de noms de canaux (ajout/suppression dynamique), sauvegarde YAML directe
- Page Config : section Utilisateurs Audio Serveur (CRUD complet, modal avec
  sélecteur de groupe, canaux entrée/sortie)
- IPC main.js : handlers server-audio-users:list/create/update/delete,
  routing:get, routing:save
- preload.js : namespaces electronAPI.serverAudioUsers et electronAPI.routing
- showModal : support du type 'select' avec options
- loadViewData : routing et config lisibles sans serveur (YAML direct)

electron/ui/styles.css

@@ -800,3 +800,157 @@ body {
     opacity: 0.3;
   }
 }
+
+/* ========== Routing View ========== */
+
+.routing-matrix-wrapper {
+  overflow-x: auto;
+}
+
+.routing-matrix-scroll {
+  overflow-x: auto;
+  max-width: 100%;
+}
+
+.routing-matrix {
+  border-collapse: collapse;
+  font-size: 0.875rem;
+  min-width: 100%;
+}
+
+.routing-matrix th,
+.routing-matrix td {
+  padding: 0.5rem 0.75rem;
+  border: 1px solid var(--border-color);
+  text-align: center;
+  vertical-align: middle;
+}
+
+.routing-matrix thead th {
+  background: var(--bg-tertiary);
+  font-weight: 600;
+  position: sticky;
+  top: 0;
+  z-index: 1;
+}
+
+.matrix-label-cell {
+  text-align: left;
+  font-weight: 600;
+  background: var(--bg-tertiary);
+  min-width: 200px;
+  position: sticky;
+  left: 0;
+  z-index: 2;
+}
+
+.matrix-group-header {
+  min-width: 110px;
+  font-size: 0.8125rem;
+  line-height: 1.4;
+}
+
+.matrix-channel-label {
+  text-align: left;
+  white-space: nowrap;
+  background: var(--bg-secondary);
+  position: sticky;
+  left: 0;
+  z-index: 1;
+}
+
+.ch-index {
+  display: inline-block;
+  background: var(--bg-primary);
+  color: var(--accent-primary);
+  font-family: 'Courier New', monospace;
+  font-size: 0.75rem;
+  padding: 0.1rem 0.4rem;
+  border-radius: 3px;
+  margin-right: 0.5rem;
+  min-width: 24px;
+  text-align: center;
+}
+
+.ch-name {
+  color: var(--text-secondary);
+  font-size: 0.8125rem;
+}
+
+.matrix-cell {
+  text-align: center;
+}
+
+.matrix-cell input[type="checkbox"] {
+  width: 18px;
+  height: 18px;
+  cursor: pointer;
+  accent-color: var(--accent-primary);
+}
+
+.routing-matrix tbody tr:hover .matrix-channel-label,
+.routing-matrix tbody tr:hover td {
+  background: rgba(74, 158, 255, 0.05);
+}
+
+/* Channel Names Editor */
+
+.channel-names-grid {
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  gap: 2rem;
+}
+
+.channel-names-col-header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  margin-bottom: 0.75rem;
+  padding-bottom: 0.5rem;
+  border-bottom: 1px solid var(--border-color);
+}
+
+.channel-names-col-header h4 {
+  font-size: 0.875rem;
+  color: var(--text-secondary);
+  text-transform: uppercase;
+  letter-spacing: 0.06em;
+  margin: 0;
+}
+
+.channel-names-list {
+  display: flex;
+  flex-direction: column;
+  gap: 0.5rem;
+}
+
+.channel-name-row {
+  display: flex;
+  align-items: center;
+  gap: 0.625rem;
+}
+
+.channel-index {
+  min-width: 58px;
+  font-size: 0.8125rem;
+  color: var(--text-secondary);
+  font-family: 'Courier New', monospace;
+  flex-shrink: 0;
+}
+
+/* Routing actions bar */
+
+.routing-actions {
+  display: flex;
+  align-items: center;
+  gap: 1rem;
+  padding: 0.5rem 0 1.5rem;
+}
+
+.routing-restart-note {
+  color: var(--accent-warning);
+}
+
+.routing-restart-note.hidden {
+  display: none;
+}