fix: Tab Mgmt intro + 6 FR descriptions in Tab/Search sections

- Tab: intro paragraph + Ctrl+Shift+Tab → Previous tab
- Search: History, Colors, Tag facets, Sort by date all → EN

frontend/locales/en.json

@@ -676,7 +676,7 @@
   "auto.209c5490": "The top bar contains the essential elements:",
   "auto.4c908ade": "Click a vault to open it and see its",
   "auto.1abf6661": "The path displayed above the content is",
-  "auto.27a2f7c1": "ObsiGate supporte l'ouverture de plusieurs\n                                fichiers simultanément dans des onglets.",
+  "auto.27a2f7c1": "ObsiGate supports opening multiple files simultaneously in tabs.",
   "auto.4bc1f00a": "Use operators to refine your",
   "auto.1a54bd69": "Combined example",
   "auto.404c8f1c": "Autocomplete helps you quickly find",
@@ -835,19 +835,19 @@
   "help.desc_085ec31f": ":\n                                    Quick select at the top of the Vault tabs",
   "help.desc_e3fce7a3": ": Opens the file in a temporary tab (preview, italic)",
   "help.desc_d186a19e": ": The Recent tab in the sidebar lists your latest files",
-  "help.desc_e5246734": ": Onglet\n                                    précédent",
+  "help.desc_e5246734": ": Previous tab",
   "help.desc_170a6982": ": Horizontal display with file name and icon",
   "help.desc_6b649b1e": ": Highlighted in accent color",
   "help.desc_ef1531ce": ": A temporary tab (italic) is replaced by the next click",
   "help.desc_5ab8c78d": ":\n                                    Stay open until manually closed",
   "help.desc_00b9572b": ":\n                                    Results ranked by TF-IDF relevance",
   "help.desc_53bfaeca": ": Navigation par\n                                    pages de 50 résultats",
-  "help.desc_4de7e318": ": Les 50\n                                    dernières recherches (localStorage)",
+  "help.desc_4de7e318": ": The 50 most recent searches (localStorage)",
   "help.desc_6b8fc728": ": ↑/↓\n                                    pour naviguer, Enter pour sélectionner",
-  "help.desc_6ebebdfd": ": Chaque type\n                                    d'opérateur a sa couleur",
-  "help.desc_cf5ccd40": ": Compteurs\n                                    par tag dans les résultats",
+  "help.desc_6ebebdfd": ": Each operator type has its color",
+  "help.desc_cf5ccd40": ": Counters by tag in results",
   "help.desc_9fec424d": ": Score\n                                    TF-IDF (défaut)",
-  "help.desc_42a81347": ": Dernière\n                                    modification",
+  "help.desc_42a81347": ": Last modified",
   "help.desc_6caffeed": ": Cliquez pour\n                                    filtrer les résultats",
   "help.desc_6a5ddef2": ": Les tags\n                                    s'adaptent au vault sélectionné",
   "help.desc_828db5da": ": Les\n                                    deux types sont combinés",