feat(ai): menu @ instantane, selecteurs agrandis et BooksLM racine (#82)

Nouvel endpoint GET /api/vault/{vault}/paths + prechargement et filtrage client du menu @ (affichage instantane des fichiers/repertoires). Selecteurs Fournisseur/Modele agrandis (0,8rem / 34px) pour s'aligner sur le reste du site. Ajout de BooksLM au menu contextuel de la racine des vaults.

frontend/js/bookslm.js

@@ -109,6 +109,10 @@ class BooksLM {
     this._menuSeq = 0;
     // Timer that hides the "done" activity indicator after a short delay.
     this._activityHideTimer = null;
+    // Cache of every indexed path per vault, backing instant `@` filtering.
+    this._pathCache = null;
+    this._pathCacheVault = null;
+    this._pathCachePromise = null;
   }
 
   _readAgentMode() {
@@ -214,6 +218,8 @@ class BooksLM {
 
     await this._loadContext();
     this._isLoading = false;
+    // Warm the `@` path cache so the mention menu appears instantly.
+    this._ensurePaths().catch(() => { /* best effort */ });
   }
 
   /** Backwards-compatible helper: open the assistant on a directory. */
@@ -349,6 +355,31 @@ class BooksLM {
     return (first && (first.name || first)) || null;
   }
 
+  /**
+   * Fetch (once per vault) the flat list of indexed paths so the `@` menu can
+   * filter files/directories instantly on the client. Falls back to an empty
+   * list on failure; callers then use the tree-search endpoint.
+   */
+  async _ensurePaths() {
+    const vault = this._activeVault();
+    if (!vault) return [];
+    if (this._pathCache && this._pathCacheVault === vault) return this._pathCache;
+    if (this._pathCachePromise && this._pathCacheVault === vault) return this._pathCachePromise;
+    this._pathCacheVault = vault;
+    this._pathCachePromise = api(`/api/vault/${encodeURIComponent(vault)}/paths?limit=5000`)
+      .then((data) => {
+        const paths = Array.isArray(data.results) ? data.results : [];
+        this._pathCache = paths;
+        return paths;
+      })
+      .catch(() => {
+        this._pathCache = [];
+        return [];
+      })
+      .finally(() => { this._pathCachePromise = null; });
+    return this._pathCachePromise;
+  }
+
   /** Open a file mentioned in an assistant answer in the main viewer. */
   async _openFileLink(path) {
     const vault = this._activeVault();
@@ -856,9 +887,19 @@ class BooksLM {
     if (!this._panel) return;
     const seq = ++this._menuSeq;
     const vault = this._activeVault();
+    const q = normalizeSearch(query);
     try {
       let results = [];
-      if (query) {
+      // Fast path: filter the prefetched flat path list on the client so the
+      // menu updates instantly while typing.
+      const cached = await this._ensurePaths();
+      if (seq !== this._menuSeq) return;
+      if (cached.length) {
+        const matches = q
+          ? cached.filter((p) => normalizeSearch(p.path).includes(q))
+          : cached;
+        results = matches.slice(0, 20);
+      } else if (query) {
         const searchVault = vault || 'all';
         const data = await api(
           `/api/tree-search?q=${encodeURIComponent(query)}&vault=${encodeURIComponent(searchVault)}`

frontend/js/ui.js

@@ -1705,6 +1705,8 @@ export const ContextMenuManager = {
     if (type === 'vault') {
       this._addItem('folder-plus', 'Nouveau dossier', () => this._createDirectory(), isReadonly);
       this._addItem('file-plus', 'Nouveau fichier', () => this._createFile(), isReadonly);
+      this._addSeparator();
+      this._addItem('brain', '🧠 BooksLM', () => { import('./bookslm.js').then(m => m.default.open(this._targetVault, '')); }, false);
     } else if (type === 'directory') {
       this._addItem('folder-plus', 'Nouveau sous-dossier', () => this._createDirectory(), isReadonly);
       this._addItem('file-plus', 'Nouveau fichier ici', () => this._createFile(), isReadonly);