Design: Text and SVG draw INTO the open sketch instead of beside it

Mirror of snaporca 1fb7786d9a (DesignPanel.cpp and DesignCanvas.cpp applied as patches;
parity 30 / 16, shared files byte-identical).

With a sketch open, Text/SVG outlines become ordinary Line entities via push_closed_lines()
instead of a separate Sketch feature carrying rigid imported_regions — so the letters can
be constrained, trimmed and extruded like anything drawn by hand. The buttons and offer
actions arm Select first when in Sketch mode, since begin_sketch() does not run until a
tool is armed.

add_imported_regions() calls reset_autoedit(): without it the glyph contours entered the
draw-then-edit queue and opened a Length field on the first segment, which freezes the
canvas. Caught on the rig, not by reading.

No sketch open: unchanged — a new Sketch feature, still dropped on a picked face.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LyRwbuq6fjn3VV9U9UvhBM

src/slic3r/GUI/DesignSketchTool.cpp

@@ -2317,6 +2317,29 @@ void DesignSketchTool::push_line(const Vec2d& a, const Vec2d& b)
     m_entities.push_back(e);
 }
 
+bool DesignSketchTool::add_imported_regions(
+    const std::vector<std::vector<std::vector<Vec2d>>>& regions)
+{
+    if (!m_active) return false;          // no session to draw into; caller makes a feature
+    const bool saved = m_construction;
+    m_construction = false;               // art is real geometry, never construction lines
+    size_t before = m_entities.size();
+    for (const auto& region : regions)
+        for (const auto& loop : region)
+            push_closed_lines(loop);      // every glyph contour, holes included
+    m_construction = saved;
+    if (m_entities.size() == before) return false;   // nothing importable — say so, do not lie
+    // Art is not "just drawn", so it must NOT enter the draw-then-edit queue. Without this the
+    // glyph contours are treated as fresh entities and a Length field opens on the first of
+    // them — on a word, that is one value editor per segment, and an open field freezes the
+    // canvas (snaporca-yce). reset_autoedit() marks every entity as already seen.
+    reset_autoedit();
+    // The new lines carry no constraints, so the solver has nothing to move; resolve anyway so
+    // the degrees-of-freedom readout counts them instead of going stale.
+    resolve_live();
+    return true;
+}
+
 void DesignSketchTool::push_closed_lines(const std::vector<Vec2d>& corners)
 {
     const size_t n = corners.size();