fix(ai): accents dans les chemins et resolution des chemins prefixes par le vault (BUG-042)

- accents : classes de caracteres Unicode (\p{L}\p{N}\p{M}) pour les motifs
  de liens et _looksLikePath (PATH_NAME_RE) -> les chemins/fichiers accentues
  produisent enfin un lien cliquable ; comparaison de chemins normalisee NFC
  (_normKey), donc une mention decomposee (e + accent combinant, style macOS)
  correspond a une entree d'index precomposee, et inversement.
- prefixe de vault : _splitVaultPrefix() retire un premier segment egal au nom
  d'un vault connu (TestVault/Recettes/Pizza Maison.md) ; _fetchPathsForVault()
  interroge l'index de CE vault sans ecraser le cache du vault actif ;
  _openFileLink/_revealPath recoivent le vault cible ; repli 'retirer le
  premier segment' si le prefixe ne correspond a aucun vault connu.

Tests : frontend IA 62/62 (+5), 9 suites JSDOM, validate-imports 36 modules,
pytest 963 passed / 6 skipped. Verifie aussi contre l'instance live sur donnees
reelles accentuees/espaces (Recettes/Preparation.md, Recettes/Pat... ) : 8/8.

tests/frontend/ai.test.mjs

@@ -463,7 +463,7 @@ async function main() {
     const revealed = [];
     b._openFileLink = (p) => { opened.push(p); return Promise.resolve(); };
     b._revealPath = (p) => { revealed.push(p); return Promise.resolve(); };
-    b._ensurePaths = async () => ([
+    b._fetchPathsForVault = async () => ([
       { path: "Mon dossier/Ma note.md", name: "Ma note.md", type: "file" },
       { path: "Mon dossier/Sous dossier", name: "Sous dossier", type: "directory" },
     ]);
@@ -474,6 +474,63 @@ async function main() {
     assert.deepEqual(revealed, ["Mon dossier/Sous dossier"], "spaced directory resolves too");
   });
 
+  // ── 12c. Accents and vault-prefixed paths ──
+  await test("_looksLikePath accepts accented names", () => {
+    const b = new BooksLM();
+    assert.equal(b._looksLikePath("Café.md"), true, "accented filename is a path");
+    assert.equal(b._looksLikePath("Recettes/Préparation.md"), true, "accented path is a path");
+    assert.ok(b._renderMarkdown("Voir `Recettes/Préparation.md`.").includes('data-path="Recettes/Préparation.md"'),
+      "accented inline code becomes a link");
+  });
+
+  await test("bare accented paths become links without the index", () => {
+    const b = new BooksLM();
+    const html = b._renderMarkdown("Ouvre Recettes/Préparation.md puis relis.");
+    assert.ok(html.includes('data-path="Recettes/Préparation.md"'), "accented bare path linkified");
+  });
+
+  await test("decomposed accents match precomposed index entries", async () => {
+    const b = new BooksLM();
+    b._activeVault = () => "TestVault";
+    b._fetchPathsForVault = async () => ([{ path: "Recettes/Préparation.md", name: "Préparation.md", type: "file" }]);
+    const opened = [];
+    b._openFileLink = (p) => { opened.push(p); return Promise.resolve(); };
+
+    // NFD input (e + combining acute) against an NFC index entry.
+    const nfd = "Recettes/Pre\u0301paration.md";
+    await b._activatePath(nfd, "file");
+    assert.deepEqual(opened, ["Recettes/Préparation.md"], "NFD mention resolves to the NFC path");
+  });
+
+  await test("_splitVaultPrefix strips a leading vault name", () => {
+    const b = new BooksLM();
+    b._vault = "TestVault";
+    assert.deepEqual(
+      b._splitVaultPrefix("TestVault/Recettes/Pizza Maison.md"),
+      { vault: "TestVault", path: "Recettes/Pizza Maison.md" },
+      "vault prefix split off",
+    );
+    assert.deepEqual(
+      b._splitVaultPrefix("Recettes/Pizza Maison.md"),
+      { vault: null, path: "Recettes/Pizza Maison.md" },
+      "no prefix when the first segment is not a vault",
+    );
+  });
+
+  await test("a vault-prefixed path opens the file in that vault", async () => {
+    const b = new BooksLM();
+    b._vault = "TestVault";
+    b._activeVault = () => "TestVault";
+    b._fetchPathsForVault = async (v) => (v === "TestVault"
+      ? [{ path: "Recettes/Pizza Maison.md", name: "Pizza Maison.md", type: "file" }]
+      : []);
+    const opened = [];
+    b._openFileLink = (p, v) => { opened.push([v, p]); return Promise.resolve(); };
+
+    await b._activatePath("TestVault/Recettes/Pizza Maison.md", "file");
+    assert.deepEqual(opened, [["TestVault", "Recettes/Pizza Maison.md"]], "opened in the named vault");
+  });
+
   await test("_renderMarkdown keeps external links external", () => {
     const b = new BooksLM();
     const html = b._renderMarkdown("[site](https://example.com/page)");