feat(assistant): #94-#97 historique permanent, sidebar IA, panneau + et bouton rond

tests/frontend/ai.test.mjs

@@ -916,16 +916,25 @@ async function main() {
     b._panel.remove();
   });
 
-  // ── 13. Session management ──
-  await test("sessions persist and can be reopened and deleted", () => {
+  // ── 13. Session management (#95/#96 — persistent backend history) ──
+  await test("sessions persist and can be reopened and deleted", async () => {
     localStorage.clear();
+    // Mock server to avoid network calls in tests
+    globalThis.fetch = async (url) => {
+      const u = String(url);
+      if (u.includes("/api/ai/bookslm/history")) {
+        if (u.includes("PUT")) return { ok: true, status: 200, json: async () => ({}) };
+        return { ok: true, status: 200, json: async () => ({ sessions: [] }) };
+      }
+      return { ok: true, status: 200, json: async () => ({}) };
+    };
     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");
+    await b._loadHistory();
+    assert.ok(b._sessions.length >= 1, "at least one session on first load (local or server)");
 
     b._messages.push({ role: "user", content: "Première question" });
     b._messages.push({ role: "assistant", content: "Réponse" });
@@ -938,7 +947,7 @@ async function main() {
     b._messages.push({ role: "user", content: "Deuxième" });
     b._saveHistory();
 
-    b._loadSession(firstId);
+    await 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);
@@ -979,16 +988,26 @@ async function main() {
     b.close();
   });
 
-  await test("legacy single-conversation history is migrated", () => {
+  await test("legacy single-conversation history is migrated", async () => {
     localStorage.clear();
+    // Mock server to avoid network calls in tests
+    globalThis.fetch = async (url) => {
+      const u = String(url);
+      if (u.includes("/api/ai/bookslm/history")) {
+        if (u.includes("PUT")) return { ok: true, status: 200, json: async () => ({}) };
+        return { ok: true, status: 200, json: async () => ({ sessions: [] }) };
+      }
+      return { ok: true, status: 200, json: async () => ({}) };
+    };
     const b = new BooksLM();
     b._mode = MODE.GENERAL;
     localStorage.setItem(
       b._legacyHistoryKey(),
       JSON.stringify([{ role: "user", content: "Ancienne conversation" }])
     );
-    b._loadHistory();
+    await b._loadHistory();
     assert.equal(b._sessions.length, 1, "legacy history imported as a session");
+    assert.ok(b._messages.length >= 1, "messages from legacy session available");
     assert.equal(b._messages[0].content, "Ancienne conversation");
   });