feat(solid history): booleans keep the solids they joined editable

With SOLIDHIST on, UNION, SUBTRACT and INTERSECT no longer reduce the
result's history to a frozen body: each solid's history joins the
result's under a boolean step, in the order the result applied them.
The Properties palette lists a composite's solids under Operand; the one
chosen shows its own geometry rows and grips, placed where it sits in
the composite, and editing it replays the whole tree. A composite read
from a file keeps its saved body; the tree is replayed only on edits.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

locales/ru-RU/opencadstudio.ftl

@@ -2333,6 +2333,7 @@ common =
     .requires-two-positive-values = Требуются два положительных значения (x,y) или одно для обоих.
     .snap-marker-color = Цвет маркера привязки
     .command-line-text-color = Цвет текста командной строки
+    .operand = Операнд
     .linetypes-loaded = Загружено типов линий: __ocs_fmt_0__.
     .geometric-center-snap = Геометрический центр
     .no-trim-option = Без обрезки