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/shared/components/EmptyState.module.scss

@@ -0,0 +1,39 @@
+@import '../../../../styles/design-tokens';
+
+.emptyState {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: $sp-2;
+  padding: $sp-8 $sp-4;
+  text-align: center;
+  color: $gray-500;
+}
+
+.icon {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 48px;
+  height: 48px;
+  border-radius: $r-full;
+  background: $navy-50;
+  color: $navy-700;
+}
+
+.title {
+  margin: 0;
+  font-family: $font-sans;
+  font-size: $fs-body;
+  font-weight: 600;
+  color: $navy-900;
+}
+
+.text {
+  margin: 0;
+  font-size: $fs-sm;
+}
+
+.action {
+  margin-top: $sp-2;
+}

src/webparts/stroyBot/shared/components/EmptyState.tsx

@@ -0,0 +1,23 @@
+import * as React from 'react';
+import { Icon, IconName } from '@tnsu/ui-kit';
+import styles from './EmptyState.module.scss';
+
+interface Props {
+  icon?: IconName;
+  title: string;
+  text?: string;
+  /** Кнопка действия под текстом (например, «+ Добавить объект»). */
+  action?: React.ReactNode;
+}
+
+// В ui-kit пока нет EmptyState — живёт здесь, позже переедет в кит.
+export const EmptyState: React.FC<Props> = ({ icon = 'info', title, text, action }) => (
+  <div className={styles.emptyState}>
+    <span className={styles.icon}>
+      <Icon name={icon} size="lg" />
+    </span>
+    <p className={styles.title}>{title}</p>
+    {text && <p className={styles.text}>{text}</p>}
+    {action && <div className={styles.action}>{action}</div>}
+  </div>
+);