i18n: fix dashboard tabs and shortcut descriptions

- Dashboard tabs: Statistiques/Récents/Partagés -> data-i18n spans
- Shortcut descriptions: added 10 help.shortcut_* keys to locales
- Tip text: added help.shortcut_tip key
- Added 3 dashboard.tab_* keys
- en.json/fr.json: 1044 -> 1059 keys

frontend/index.html

@@ -947,8 +947,8 @@
                                         data-lucide="bar-chart-3"
                                         style="width: 14px; height: 14px"
                                     ></i>
-                                    Statistiques
-                                </button>
+                                    <span data-i18n="dashboard.tab_stats">Statistiques</span>
+                                    </button>
                                 <button
                                     class="dashboard-tab"
                                     data-tab="bookmarks"
@@ -964,15 +964,15 @@
                                         data-lucide="clock"
                                         style="width: 14px; height: 14px"
                                     ></i>
-                                    Récents
-                                </button>
+                                    <span data-i18n="dashboard.tab_recent">Récents</span>
+                                    </button>
                                 <button class="dashboard-tab" data-tab="shared">
                                     <i
                                         data-lucide="share-2"
                                         style="width: 14px; height: 14px"
                                     ></i>
-                                    Partagés
-                                </button>
+                                    <span data-i18n="dashboard.tab_shared">Partagés</span>
+                                    </button>
                             </div>
 
                             <!-- Stats Panel -->
@@ -1014,7 +1014,7 @@
                                             <span class="qh-kbd"
                                                 >Ctrl+Shift+Space</span
                                             >
-                                            <span class="qh-desc"
+                                            <span class="qh-desc" data-i18n="help.shortcut_command_palette"
                                                 >Palette de commandes</span
                                             >
                                         </div>
@@ -1029,7 +1029,7 @@
                                         </div>
                                         <div class="qh-row">
                                             <span class="qh-kbd">Ctrl+K</span>
-                                            <span class="qh-desc"
+                                            <span class="qh-desc" data-i18n="help.shortcut_focus_search"
                                                 >Focus barre de recherche</span
                                             >
                                         </div>
@@ -1056,7 +1056,7 @@
                                         </div>
                                         <div class="qh-row">
                                             <span class="qh-kbd">Esc</span>
-                                            <span class="qh-desc"
+                                            <span class="qh-desc" data-i18n="help.shortcut_close_editor"
                                                 >Fermer l'editeur / modale</span
                                             >
                                         </div>
@@ -1076,7 +1076,7 @@
                                         </div>
                                         <div class="qh-row">
                                             <span class="qh-kbd">F1</span>
-                                            <span class="qh-desc"
+                                            <span class="qh-desc" data-i18n="help.shortcut_forge_help"
                                                 >Aide de l'editeur Forge</span
                                             >
                                         </div>