R14-TQ2-PQ1-R3-R2 Live Progress First-Paint + Monitor Scroll Reliability

app.py

@@ -1039,6 +1039,15 @@ def _render_task_status_once(lang_code: str) -> None:
     if not task_id:
         return
     status = str(task.get("status") or "")
+
+    # First-paint invariant: render useful, localized progress and manuscript
+    # placeholders before any browser bridge call that may yield once via
+    # st.stop(). The browser watcher mutates these stable DOM targets in place
+    # after the bridge handshake, so no duplicate monitor/preview is needed.
+    st.session_state["sp_last_ui_task_status"] = status
+    _render_monitor_box(task, lang_code)
+    _render_checkpoint_preview(task, lang_code)
+
     if status in ACTIVE_TASK_STATUSES:
         try:
             result = generation_task_status(task_id)
@@ -1055,8 +1064,6 @@ def _render_task_status_once(lang_code: str) -> None:
             status = str(task.get("status") or "")
 
     st.session_state["sp_last_ui_task_status"] = status
-    _render_monitor_box(task, lang_code)
-    _render_checkpoint_preview(task, lang_code)
 
     if status == "resumable":
         resume_capable, _ = _local_resume_capability(task)
@@ -1127,7 +1134,7 @@ def _inject_generation_action_scroll(mode: str) -> None:
 
 
 def _scroll_to_generation_action_once() -> None:
-    """One-time post-launch/resume scroll to the live manuscript, never per checkpoint."""
+    """One-time post-launch/resume scroll to the monitor/live manuscript."""
     if not bool(st.session_state.get("sp_scroll_to_generation_action")):
         return
     st.session_state["sp_scroll_to_generation_action"] = False
@@ -1140,14 +1147,20 @@ def _scroll_to_generation_action_once() -> None:
           const parentDocument = window.parent.document;
           const fallbackId = {json.dumps(fallback_id)};
           let done = false;
-          const locate = () => {{
+          const locate = (allowFallback = false) => {{
             if (done) return;
-            const target = parentDocument.getElementById('sp-live-manuscript-shell') || parentDocument.getElementById(fallbackId);
+            const target =
+              parentDocument.getElementById('sp-task-monitor-anchor') ||
+              parentDocument.getElementById('sp-live-manuscript-shell') ||
+              (allowFallback ? parentDocument.getElementById(fallbackId) : null);
             if (!target) return;
             done = true;
             target.scrollIntoView({{behavior:'auto', block:'center'}});
           }};
-          [0, 40, 100, 220, 450, 800].forEach((delay) => window.parent.setTimeout(locate, delay));
+          [0, 60, 140, 300, 650, 1000, 1600].forEach((delay) =>
+            window.parent.setTimeout(() => locate(false), delay)
+          );
+          window.parent.setTimeout(() => locate(true), 2200);
         }})();
         </script>
         """,
@@ -1280,7 +1293,10 @@ if st.session_state.get("sp_payment_required"):
 _task_for_monitor = st.session_state.get("sp_generation_task") or {}
 if str(_task_for_monitor.get("task_id") or "").strip():
     st.markdown("<div id='sp-task-monitor-anchor'></div>", unsafe_allow_html=True)
-    _render_task_status_once(lang_code)
+    # Install the one-time navigation script before task-status bridge calls.
+    # If the first bridge handshake yields via st.stop(), the browser still
+    # receives the anchor and can position the user at visible task progress.
     _scroll_to_generation_action_once()
+    _render_task_status_once(lang_code)