i18n: complete audit — 55 new keys, all hardcoded strings converted to t()

- Added 4 missing keys: button.cancel, toast.dir_renamed, toast.file_deleted, toast.file_renamed
- Replaced 41 hardcoded showToast() strings with t() calls across 13 JS files
- Replaced 10 hardcoded textContent/title/innerHTML strings with t() calls
- Fixed theme labels: Sombre/Clair -> t('theme.dark')/t('theme.light')
- Fixed vault selector: Tous les vaults -> t('help.all_vaults')
- Both locale files: 983 -> 1032 keys, perfectly matched
- Bidirectional EN<->FR switching verified in browser

frontend/js/dashboard.js

@@ -83,7 +83,7 @@ const DashboardSharedWidget = {
         e.stopPropagation();
         const url = b.dataset.url;
         try { await navigator.clipboard.writeText(url); } catch { const ta = document.createElement("textarea"); ta.value=url; ta.style.position="fixed"; ta.style.left="-9999px"; document.body.appendChild(ta); ta.select(); document.execCommand("copy"); document.body.removeChild(ta); }
-        showToast("Lien copié !", "success");
+        showToast(t("config.link_copied"), "success");
       }));
       grid.querySelectorAll(".shared-open-btn").forEach(b => b.addEventListener("click", (e) => {
         e.stopPropagation();
@@ -93,7 +93,7 @@ const DashboardSharedWidget = {
       grid.querySelectorAll(".shared-revoke-btn").forEach(b => b.addEventListener("click", async (e) => {
         e.stopPropagation();
         await api(`/api/share/${b.dataset.id}`, { method: "DELETE" });
-        showToast("Partage révoqué", "success");
+        showToast(t("config.share_revoked"), "success");
         this.load();
       }));
       grid.querySelectorAll(".shared-card").forEach(card => card.addEventListener("click", () => {
@@ -147,7 +147,7 @@ const DashboardConflictsWidget = {
   async _resolve(d, action) {
     try {
       await api("/api/conflicts/resolve", { method: "POST", body: JSON.stringify({ vault: d.vault, conflict_path: d.conflict, original_path: d.original, action }) });
-      showToast("Conflit résolu", "success");
+      showToast(t("dashboard.conflict_resolved"), "success");
       this.load();
     } catch (err) { showToast("Erreur: " + err.message, "error"); }
   }
@@ -204,7 +204,7 @@ const DashboardRecentWidget = {
       });
     } catch (err) {
       console.error("Failed to toggle bookmark:", err);
-      showToast("Erreur lors de l'épinglage", "error");
+      showToast(t("dashboard.pin_error"), "error");
     }
   },