feat: add StroyBot app shell with URL routing

One web part replaces the separate stroy-bot-* web parts. The section and
its parameters live in the page query string (?page=objects&projectId=5),
so links can be copied, opened in a new tab and the browser Back button works.

- shared config: site/Dataverse/API addresses, list and table names
- HTTP layer behind IHttpClient so repositories can be unit-tested
- ui-kit AppLayout + Sidebar, placeholder for sections not ported yet
- migration checklist with every feature of the old web parts
- design tokens mirrored from ui-kit instead of 8 copies

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/webparts/stroyBot/app/routing/RouterContext.tsx

@@ -0,0 +1,49 @@
+import * as React from 'react';
+import { buildSearch, IRoute, parseRoute } from './routes';
+
+interface IRouterValue {
+  route: IRoute;
+  /** Перейти в раздел: меняет адрес (history.pushState) и перерисовывает приложение. */
+  navigate: (route: IRoute) => void;
+  /** Полный адрес раздела — для настоящих ссылок (Ctrl+клик, «открыть в новой вкладке»). */
+  buildHref: (route: IRoute) => string;
+}
+
+const RouterContext = React.createContext<IRouterValue | undefined>(undefined);
+
+function readCurrentRoute(): IRoute {
+  return parseRoute(window.location.search);
+}
+
+function buildHref(route: IRoute): string {
+  return `${window.location.pathname}${buildSearch(route, window.location.search)}`;
+}
+
+export const RouterProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
+  const [route, setRoute] = React.useState<IRoute>(readCurrentRoute);
+
+  // Кнопки «назад/вперёд» браузера меняют адрес без нашего участия — перечитываем маршрут.
+  React.useEffect(() => {
+    const onPopState = (): void => setRoute(readCurrentRoute());
+    window.addEventListener('popstate', onPopState);
+    return () => window.removeEventListener('popstate', onPopState);
+  }, []);
+
+  const navigate = React.useCallback((next: IRoute): void => {
+    window.history.pushState(undefined, '', buildHref(next));
+    setRoute(next);
+    window.scrollTo(0, 0);
+  }, []);
+
+  const value = React.useMemo<IRouterValue>(() => ({ route, navigate, buildHref }), [route, navigate]);
+
+  return <RouterContext.Provider value={value}>{children}</RouterContext.Provider>;
+};
+
+export function useRouter(): IRouterValue {
+  const router = React.useContext(RouterContext);
+  if (!router) {
+    throw new Error('useRouter: компонент отрисован вне RouterProvider');
+  }
+  return router;
+}