feat(ai): rendu Markdown, liens fichiers/paths et sessions (#80)

Assistant IA (BooksLM) :

- renderer Markdown complet (titres, listes, tableaux, citations, code) avec echappement HTML

- mentions fichiers/paths cliquables : ouverture du fichier / revelation dans l'arborescence

- gestion multi-sessions par contexte (historique, rechargement, suppression, migration)

- i18n FR/EN, aide in-app, styles, tests frontend (24)

tests/frontend/ai.test.mjs

@@ -102,7 +102,7 @@ async function main() {
 
   const ai = await import(pathToFileURL(path.join(JS_DIR, "ai.js")).href);
   const bookslmMod = await import(pathToFileURL(path.join(JS_DIR, "bookslm.js")).href);
-  const { BooksLM } = bookslmMod;
+  const { BooksLM, MODE } = bookslmMod;
   const { collectOpenDocuments, documentsSignature } = bookslmMod;
 
   // ── 1. Rewrite modal resolves with the typed instruction ──
@@ -357,11 +357,162 @@ async function main() {
     assert.ok(actions.querySelector(".bookslm-btn-export"));
     assert.ok(actions.querySelector(".bookslm-btn-fullscreen"));
     assert.ok(actions.querySelector(".bookslm-btn-close"));
+    assert.ok(actions.querySelector(".bookslm-btn-history"), "session history button");
+    assert.ok(panel.querySelector(".bookslm-history-menu"), "session history menu host");
     assert.ok(panel.querySelector(".bookslm-toolbar .bookslm-picker-host"), "picker on its own toolbar row");
     assert.ok(panel.querySelector(".bookslm-input-hint"), "keyboard hint shown");
     panel.remove();
   });
 
+  // ── 11. Formatted markdown rendering ──
+  await test("_renderMarkdown renders headings, lists, code and tables", () => {
+    const b = new BooksLM();
+    const html = b._renderMarkdown([
+      "# Title",
+      "",
+      "Some **bold** and `code` text.",
+      "",
+      "- one",
+      "- two",
+      "",
+      "| A | B |",
+      "| --- | --- |",
+      "| 1 | 2 |",
+      "",
+      "```js",
+      "const x = 1;",
+      "```",
+    ].join("\n"));
+    assert.ok(html.includes("<h1>Title</h1>"), "heading rendered");
+    assert.ok(html.includes("<strong>bold</strong>"), "bold rendered");
+    assert.ok(html.includes("<code>code</code>"), "inline code rendered");
+    assert.ok(html.includes("<ul><li>one</li><li>two</li></ul>"), "list rendered");
+    assert.ok(html.includes("<table>") && html.includes("<th>A</th>") && html.includes("<td>1</td>"), "table rendered");
+    assert.ok(html.includes("language-js") && html.includes("const x = 1;"), "fenced code rendered");
+  });
+
+  await test("_renderMarkdown escapes model HTML output", () => {
+    const b = new BooksLM();
+    const html = b._renderMarkdown('<img src=x onerror="alert(1)">');
+    assert.ok(!html.includes("<img"), "raw HTML must be escaped");
+    assert.ok(html.includes("&lt;img"), "escaped output present");
+  });
+
+  // ── 12. File/path mentions become clickable links ──
+  await test("_renderMarkdown turns file and path mentions into links", () => {
+    const b = new BooksLM();
+    const html = b._renderMarkdown("Ouvre `notes/a.md` puis `projets/2026` et [le guide](docs/guide.md).");
+    assert.ok(html.includes('class="bookslm-path-link"'), "path links rendered");
+    assert.ok(html.includes('data-path="notes/a.md"') && html.includes('data-kind="file"'), "file link classified");
+    assert.ok(html.includes('data-path="projets/2026"') && html.includes('data-kind="dir"'), "dir link classified");
+    assert.ok(html.includes('data-path="docs/guide.md"'), "markdown link linkified");
+  });
+
+  await test("_renderMarkdown keeps external links external", () => {
+    const b = new BooksLM();
+    const html = b._renderMarkdown("[site](https://example.com/page)");
+    assert.ok(html.includes('href="https://example.com/page"'), "external link kept");
+    assert.ok(!html.includes("bookslm-path-link"), "external link not treated as a vault path");
+  });
+
+  await test("clicking a path link opens a file or reveals a directory", () => {
+    const b = new BooksLM();
+    b._panel = b._render();
+    document.body.appendChild(b._panel);
+    const opened = [];
+    const revealed = [];
+    b._openFileLink = (p) => { opened.push(p); return Promise.resolve(); };
+    b._revealPath = (p) => { revealed.push(p); return Promise.resolve(); };
+
+    const container = b._panel.querySelector(".bookslm-messages");
+    container.innerHTML = b._renderMarkdown("`notes/a.md` et `dossier/sous-dossier`");
+    const fileLink = container.querySelector('a[data-kind="file"]');
+    const dirLink = container.querySelector('a[data-kind="dir"]');
+    assert.ok(fileLink, "file link rendered");
+    assert.ok(dirLink, "dir link rendered");
+    fileLink.click();
+    dirLink.click();
+    assert.deepEqual(opened, ["notes/a.md"]);
+    assert.deepEqual(revealed, ["dossier/sous-dossier"]);
+    b._panel.remove();
+  });
+
+  // ── 13. Session management ──
+  await test("sessions persist and can be reopened and deleted", () => {
+    localStorage.clear();
+    const b = new BooksLM();
+    b._panel = document.createElement("div");
+    b._mode = MODE.DIRECTORY;
+    b._vault = "VaultSessions";
+    b._directory = "notes";
+    b._loadHistory();
+    assert.equal(b._sessions.length, 1, "one session created on first load");
+
+    b._messages.push({ role: "user", content: "Première question" });
+    b._messages.push({ role: "assistant", content: "Réponse" });
+    b._saveHistory();
+    const firstId = b._currentSessionId;
+
+    b.newConversation();
+    assert.equal(b._sessions.length, 2, "new conversation adds a session");
+    assert.notEqual(b._currentSessionId, firstId, "current session switched");
+    b._messages.push({ role: "user", content: "Deuxième" });
+    b._saveHistory();
+
+    b._loadSession(firstId);
+    assert.equal(b._messages.length, 2, "previous session messages restored");
+    assert.equal(b._messages[0].content, "Première question");
+    const first = b._sessions.find((s) => s.id === firstId);
+    assert.ok(first && first.title.includes("Première"), "session titled from first user message");
+
+    b._deleteSession(firstId);
+    assert.equal(b._sessions.length, 1, "session deleted");
+    assert.ok(!b._sessions.find((s) => s.id === firstId), "deleted session gone");
+  });
+
+  await test("history menu lists saved sessions", () => {
+    localStorage.clear();
+    const b = new BooksLM();
+    b._mode = MODE.DIRECTORY;
+    b._vault = "VaultMenu";
+    b._directory = "d";
+    b._loadHistory();
+    b._messages.push({ role: "user", content: "Hello menu" });
+    b._saveHistory();
+
+    b._panel = b._render();
+    document.body.appendChild(b._panel);
+    b._renderHistoryMenu();
+    const items = b._panel.querySelectorAll(".bookslm-history-item");
+    assert.equal(items.length, 1, "one session listed");
+    assert.ok(items[0].textContent.includes("Hello menu"), "session title shown");
+    b._panel.remove();
+  });
+
+  await test("newConversation before open defers a fresh session", async () => {
+    localStorage.clear();
+    const b = new BooksLM();
+    b.newConversation();
+    assert.equal(b._pendingNewSession, true, "fresh session deferred");
+    await b.openContext({ mode: MODE.GENERAL });
+    assert.equal(b._pendingNewSession, false, "deferred session applied on open");
+    assert.equal(b._sessions.length, 1, "fresh session created");
+    b.close();
+  });
+
+  await test("legacy single-conversation history is migrated", () => {
+    localStorage.clear();
+    const b = new BooksLM();
+    b._mode = MODE.GENERAL;
+    localStorage.setItem(
+      b._legacyHistoryKey(),
+      JSON.stringify([{ role: "user", content: "Ancienne conversation" }])
+    );
+    b._loadHistory();
+    assert.equal(b._sessions.length, 1, "legacy history imported as a session");
+    assert.equal(b._messages[0].content, "Ancienne conversation");
+  });
+
   // ── Summary ──
   console.log(`\n${passCount}/${testCount} tests passed`);
   if (passCount !== testCount) {