feat: finalisation split view #75 — boutons, nav clavier, palette, ROADMAP

Ajouts:
- C3: Boutons Split ⊞→ ⊞↓ dans la barre d'onglets (visibles au survol)
- C2: Ctrl+Alt+←/→/↑/↓ navigation entre panneaux
- C2: Ctrl+Shift+Alt+W fermer tous les autres panneaux
- H1: 5 commandes palette (Split R/D, Close Pane, Focus Next/Prev)
- ROADMAP.md: section 75 mise à jour avec statut 80% complété

CSS: .tab-split-buttons, .tab-split-btn avec opacity hover

frontend/js/palette.js

@@ -51,6 +51,12 @@ function getCMDS() {
   { id:'reindex',      label:'🔄 '+t('vault.reindex'),          desc:t('palette.reindex_desc'),          cat:'Actions', act:async()=>{close();try{await api('/api/index/reload');showToast(t('sync.index_reloaded'),'success');}catch{showToast(t('common.error'),'error');}} },
   { id:'help',         label:'❓ '+t('help.help_title'),        desc:t('palette.help_desc'),             cat:'Système', act:()=>{close();const b=document.getElementById('help-open-btn');if(b)b.click();} },
   { id:'config',       label:t('palette.cmd_config'),           desc:t('palette.cmd_config_desc'),         cat:'Système', act:()=>{close();const b=document.getElementById('config-open-btn');if(b)b.click();} },
+  // Pane / Split commands
+  { id:'split-right',  label:'⊞→ Diviser à droite',              desc:'Crée un panneau à droite avec cet onglet',                cat:'Panneaux', act:()=>{close();if(window.PaneManager)window.PaneManager.splitRight();} },
+  { id:'split-down',   label:'⊞↓ Diviser en bas',                desc:'Crée un panneau en dessous avec cet onglet',              cat:'Panneaux', act:()=>{close();if(window.PaneManager)window.PaneManager.splitDown();} },
+  { id:'close-pane',   label:'✕ Fermer le panneau actif',        desc:'Ferme le panneau actif et tous ses onglets',              cat:'Panneaux', act:()=>{close();if(window.PaneManager&&window.PaneManager.isSplit())window.PaneManager.closeActivePane();} },
+  { id:'focus-next',   label:'→ Panneau suivant',                desc:'Active le panneau suivant (Ctrl+Alt+→)',                  cat:'Panneaux', act:()=>{close();if(window.PaneManager&&window.PaneManager.isSplit()){const n=(window.PaneManager.activePaneId+1)%window.PaneManager.panes.length;window.PaneManager.setActivePane(n);}} },
+  { id:'focus-prev',   label:'← Panneau précédent',              desc:'Active le panneau précédent (Ctrl+Alt+←)',                cat:'Panneaux', act:()=>{close();if(window.PaneManager&&window.PaneManager.isSplit()){const n=(window.PaneManager.activePaneId-1+window.PaneManager.panes.length)%window.PaneManager.panes.length;window.PaneManager.setActivePane(n);}} },
   ];
   return _cmdsCache;
 }

frontend/js/pane-manager.js

@@ -46,6 +46,37 @@ function createPaneTabManager(paneId) {
         this._tabList = document.getElementById('tab-list-' + paneId);
       if (!this._contentArea)
         this._contentArea = document.getElementById('content-area-' + paneId);
+
+      // Add split buttons to the tab bar (right side)
+      this._ensureSplitButtons();
+    },
+
+    _ensureSplitButtons() {
+      if (!this._tabBar) return;
+      // Remove existing split buttons if any
+      const existing = this._tabBar.querySelector('.tab-split-buttons');
+      if (existing) existing.remove();
+
+      const btns = document.createElement('div');
+      btns.className = 'tab-split-buttons';
+      btns.innerHTML = `
+        <button class="tab-split-btn" title="Diviser à droite (Ctrl+Alt+\\)" data-action="split-right">
+          <i data-lucide="panel-right" style="width:13px;height:13px"></i>
+        </button>
+        <button class="tab-split-btn" title="Diviser en bas (Ctrl+Alt+Shift+\\)" data-action="split-down">
+          <i data-lucide="panel-bottom" style="width:13px;height:13px"></i>
+        </button>
+      `;
+      btns.querySelector('[data-action="split-right"]').addEventListener('click', (e) => {
+        e.stopPropagation();
+        if (window.PaneManager) window.PaneManager.splitRight();
+      });
+      btns.querySelector('[data-action="split-down"]').addEventListener('click', (e) => {
+        e.stopPropagation();
+        if (window.PaneManager) window.PaneManager.splitDown();
+      });
+      this._tabBar.appendChild(btns);
+      if (typeof safeCreateIcons === 'function') safeCreateIcons();
     },
 
     getContentArea() {
@@ -1063,10 +1094,36 @@ if (typeof window !== 'undefined') {
         e.preventDefault();
         PaneManager.splitDown();
       }
+      // Close active pane
       if (e.ctrlKey && e.altKey && !e.shiftKey && (e.key === 'w' || e.key === 'W') && PaneManager.isSplit()) {
         e.preventDefault();
         PaneManager.closeActivePane();
       }
+      // Close all other panes
+      if (e.ctrlKey && e.shiftKey && e.altKey && (e.key === 'w' || e.key === 'W') && PaneManager.isSplit()) {
+        e.preventDefault();
+        PaneManager.closeOtherPanes();
+      }
+      // Navigate between panes
+      if (e.ctrlKey && e.altKey && PaneManager.isSplit()) {
+        if (e.key === 'ArrowRight') {
+          e.preventDefault();
+          const next = (PaneManager.activePaneId + 1) % PaneManager.panes.length;
+          PaneManager.setActivePane(next);
+        } else if (e.key === 'ArrowLeft') {
+          e.preventDefault();
+          const prev = (PaneManager.activePaneId - 1 + PaneManager.panes.length) % PaneManager.panes.length;
+          PaneManager.setActivePane(prev);
+        } else if (e.key === 'ArrowDown' && PaneManager.layout === 'vertical') {
+          e.preventDefault();
+          const next = (PaneManager.activePaneId + 1) % PaneManager.panes.length;
+          PaneManager.setActivePane(next);
+        } else if (e.key === 'ArrowUp' && PaneManager.layout === 'vertical') {
+          e.preventDefault();
+          const prev = (PaneManager.activePaneId - 1 + PaneManager.panes.length) % PaneManager.panes.length;
+          PaneManager.setActivePane(prev);
+        }
+      }
     });
     // Init — wait for DOM + singleton TabManager to be ready
     setTimeout(() => {

frontend/style.css

@@ -6526,6 +6526,41 @@ body.popup-mode .content-area {
   scrollbar-width: thin;
 }
 
+/* Split buttons in tab bar */
+.tab-split-buttons {
+  display: flex;
+  align-items: center;
+  gap: 2px;
+  padding: 0 4px;
+  flex-shrink: 0;
+  opacity: 0.3;
+  transition: opacity 150ms ease;
+}
+
+.tab-bar:hover .tab-split-buttons,
+.tab-split-buttons:hover {
+  opacity: 1;
+}
+
+.tab-split-btn {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  width: 24px;
+  height: 24px;
+  border: none;
+  border-radius: 4px;
+  background: transparent;
+  color: var(--text-muted);
+  cursor: pointer;
+  transition: background 100ms ease, color 100ms ease;
+}
+
+.tab-split-btn:hover {
+  background: var(--bg-hover);
+  color: var(--accent);
+}
+
 .tab-list::-webkit-scrollbar {
   height: 3px;
 }