fix(ai): les clics ne font plus sauter la conversation au bas (BUG-059); tableaux markdown corrects dans create_pdf (#92)

frontend/js/bookslm.js

@@ -43,6 +43,25 @@ const PANEL_MIN_WIDTH = 320;
 const PANEL_MAX_WIDTH = 1000;
 const PANEL_WIDTH_KEY = 'obsigate-bookslm-width';
 
+/**
+ * BUG-059 — Is this pointer press a scrollbar drag (and only that)?
+ *
+ * Only genuine scroll gestures may release the top-pinning of the latest
+ * question (wheel / touchmove / scrollbar drag). A scrollbar drag reports the
+ * scrollable container itself as the event target and lands inside the
+ * vertical scrollbar gutter. A plain click anywhere in the content — a link,
+ * a file path, the steps toggle, text selection — must NOT unpin: clearing
+ * the anchor padding would clamp the scroll position and jump the whole
+ * thread to the bottom of the conversation window.
+ */
+export function isScrollbarPress(target, clientX, container) {
+  if (!container || target !== container) return false;
+  const rect = container.getBoundingClientRect();
+  if (!rect || !Number.isFinite(rect.right)) return false;
+  const GUTTER = 24; // conservative vertical-scrollbar width estimate
+  return clientX >= rect.right - GUTTER;
+}
+
 /**
  * Accent- and case-insensitive normalization used to match `/` commands and
  * `@` mentions: skill ids/labels and vault paths may contain accented
@@ -985,7 +1004,12 @@ class BooksLM {
       };
       messagesEl.addEventListener('wheel', unpin, { passive: true });
       messagesEl.addEventListener('touchmove', unpin, { passive: true });
-      messagesEl.addEventListener('mousedown', unpin, { passive: true });
+      // BUG-059: a scrollbar drag only — a plain click on the content must
+      // not unpin (it would clear the anchor padding and jump the thread to
+      // the bottom of the window).
+      messagesEl.addEventListener('mousedown', (e) => {
+        if (isScrollbarPress(e.target, e.clientX, messagesEl)) unpin();
+      }, { passive: true });
     }
 
     // Close the session / command menus when clicking elsewhere in the panel.