fix(assistant): #91 bulle utilisateur elargie (81% du fil) + ancrage de la question des l'envoi ; docs: feuille de route outils #92

tests/frontend/ai.test.mjs

@@ -235,6 +235,39 @@ async function main() {
       panel.remove();
     });
 
+    await test("the placeholder render keeps the anchor (no scroll reset before first token)", async () => {
+      // Regression: the assistant placeholder used to be rendered while
+      // `_isLoading` was still false, so it took the "restore previous
+      // scroll" branch and cancelled the anchor — the submitted post stayed
+      // at the bottom until the first streamed token.
+      const b = new BooksLM();
+      const panel = b._render();
+      b._panel = panel;
+      document.body.appendChild(panel);
+      const renders = [];
+      const realRender = b._renderMessages.bind(b);
+      b._renderMessages = (opts) => { renders.push(opts || {}); realRender(opts || {}); };
+      b._setActivity = () => {};
+      b._saveHistory = () => {};
+      b._postChat = async () => ({
+        ok: true,
+        status: 200,
+        body: { getReader: () => ({ read: async () => ({ done: true }) }) },
+      });
+      panel.querySelector("textarea").value = "Question ancrée";
+      await b._sendMessage();
+      // Two renders happen on send: the user post and the assistant
+      // placeholder — both must request the anchor.
+      assert.ok(renders.length >= 2, `expected >=2 renders, got ${renders.length}`);
+      assert.equal(renders[0].anchor, true, "user post render anchors");
+      assert.equal(renders[1].anchor, true, "placeholder render anchors too");
+      // Both must be instant: the question has to be at the top when the
+      // answer starts arriving, not after a scroll animation.
+      assert.equal(renders[0].instant, true, "user post anchors instantly");
+      assert.equal(renders[1].instant, true, "placeholder anchors instantly");
+      panel.remove();
+    });
+
     await test("assistant answer shows a discreet provider/model tag", () => {
       const b = new BooksLM();
       const panel = b._render();