fix: partage dirigé — dossier Partage virtuel + ouverture en onglet #196

- _resolve_shared_file: home-<user>/Partage/<f> -> fichier source (/api/file, raw, download)
- clic dossier Partage: dépliage sans navigation (fix Directory not found)
- fichiers reçus ouverts en onglet applicatif (arbre, recherche, dashboard)
- POST /api/share: path vide/null rejeté (400) — un share path:null cassait /api/shares
- +2 tests (13 total)

frontend/js/dashboard.js

@@ -68,8 +68,10 @@ const DashboardSharedWidget = {
           : `<button class="shared-copy-btn" data-url="${window.location.origin}/s/${s.token}">${t('dashboard.copy_btn')}</button>
              <button class="shared-open-btn">${t('dashboard.open_btn')}</button>
              <button class="shared-revoke-btn" data-id="${s.id}">🗑</button>`;
+        const cardVault = received ? `home-${me}` : s.vault;
+        const cardPath = received ? `Partage/${(s.path || "").split("/").pop()}` : s.path;
         return `
-        <div class="shared-card" data-vault="${escapeHtml(s.vault)}" data-path="${escapeHtml(s.path)}" data-token="${s.token}" data-received="${received ? "1" : ""}">
+        <div class="shared-card" data-vault="${escapeHtml(cardVault)}" data-path="${escapeHtml(cardPath)}" data-token="${s.token}" data-received="${received ? "1" : ""}">
           <div class="shared-card-header">
             <i data-lucide="file-text" style="width:14px;height:14px"></i>
             <span class="shared-card-title">${escapeHtml(s.path.split("/").pop().replace(/\\.md$/i, ""))}</span>
@@ -93,10 +95,7 @@ const DashboardSharedWidget = {
       grid.querySelectorAll(".shared-open-btn").forEach(b => b.addEventListener("click", (e) => {
         e.stopPropagation();
         const card = b.closest(".shared-card");
-        if (card && card.dataset.received === "1" && card.dataset.token) {
-          window.open(`/s/${card.dataset.token}`, "_blank");
-          return;
-        }
+        // #196 : onglet applicatif — /api/file résout Partage/ vers la source.
         if (card) TabManager.openPreview(card.dataset.vault, card.dataset.path);
       }));
       grid.querySelectorAll(".shared-revoke-btn").forEach(b => b.addEventListener("click", async (e) => {
@@ -106,10 +105,6 @@ const DashboardSharedWidget = {
         this.load();
       }));
       grid.querySelectorAll(".shared-card").forEach(card => card.addEventListener("click", () => {
-        if (card.dataset.received === "1" && card.dataset.token) {
-          window.open(`/s/${card.dataset.token}`, "_blank");
-          return;
-        }
         TabManager.openPreview(card.dataset.vault, card.dataset.path);
       }));
     } catch (err) { if (empty) empty.style.display = ""; }