fix(console): stop the Clear button crashing the tab

render() computes visible_indices_ (indices into model_) once per frame at the
top, before the toolbar. The toolbar's Clear button called clear() → model_.clear(),
emptying model_ mid-frame (the "cleared" marker is only queued, drained next
frame). renderOutput() then indexed model_[visible_indices_[vi]] with the stale
indices → out-of-bounds → crash.

clear() now also drops visible_indices_ and the selection (both hold line indices
into model_), so this frame's renderOutput iterates zero lines and computeVisibleLines
rebuilds them next frame. The right-click "Clear console" menu item now routes
through clear() instead of a bare model_.clear() so it's covered too.

Adversarially verified: no other same-frame path indexes the emptied model
(fold-toggle, ingest, and selectAll are bounds-guarded).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/windows/console_tab.cpp

@@ -511,8 +511,7 @@ void ConsoleTab::renderToolbar(ConsoleCommandExecutor& exec)
 
     // Clear button
     if (TactileButton(TR("console_clear"), ImVec2(0, 0), schema::UI().resolveFont("button"))) {
-        clear();
-        selection_.clear();
+        clear();   // also drops the stale visible_indices_ + selection (see ConsoleTab::clear)
     }
     
     ImGui::SameLine();
@@ -1183,9 +1182,9 @@ void ConsoleTab::drawOutputContextMenu()
     }
     ImGui::Separator();
     if (ImGui::MenuItem(TR("console_clear_console"))) {
-        // View-only clear (main thread) — drop the visible lines and the selection.
-        model_.clear();
-        selection_.clear();
+        // View-only clear — route through clear() so the stale visible_indices_/selection are dropped too
+        // (a bare model_.clear() mid-frame would leave renderOutput() indexing the emptied model_ → crash).
+        clear();
     }
     ImGui::EndPopup();
 }
@@ -2004,6 +2003,12 @@ void ConsoleTab::clear()
     // View-only clear (main thread). The executor keeps its own log cursors, so new output
     // still appends. The "cleared" line is ingested and appears on the next frame's drain.
     model_.clear();
+    // visible_indices_ was computed at the top of render() (line 311), BEFORE the toolbar's Clear button
+    // ran; those indices now point past the emptied model_. renderOutput() (this same frame, after the
+    // toolbar) indexes model_[visible_indices_[vi]] — so drop them (and the selection, which also holds
+    // line indices) here to avoid an out-of-bounds crash. computeVisibleLines() rebuilds them next frame.
+    visible_indices_.clear();
+    selection_.clear();
     stop_confirm_pending_ = false;   // a pending 'stop' confirmation is cancelled by clearing
     addLine(TR("console_cleared"), ConsoleChannel::Info);
 }