v1.5.6: boneyard-js skeleton migration, TanStack Query refactor, rate-limit config

- Replace hand-coded skeleton CSS/JSX with boneyard-js auto-generated bones
- Remove skeleton.css and @keyframes shimmer from base.css
- Add <Skeleton> wrappers with fixtures to all 25+ page components
- Generate 20 bone captures via boneyard CLI (CDP auth-gated capture)
- Refactor data fetching from useEffect+useState to TanStack Query
- Extract query hooks into src/admin/lib/queries/ and apiAdapter
- Add usePaginatedQuery hook replacing useApiCall/useListData
- Fix parseFloat || 0 anti-pattern in OfferDetail and OffersTemplates inputs
- Fix customer_id mandatory validation on offer creation
- Fix leave-requests comma-separated status filter (Prisma enum in: [])
- Add cross-entity cache invalidation for orders/offers/invoices/projects
- Make rate limits configurable via env vars (RATE_LIMIT_MAX, RATE_LIMIT_REFRESH, etc.)
- Add boneyard.config.json with routes and breakpoints

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/admin/fixtures/ProjectFileManagerFixture.tsx

@@ -0,0 +1,53 @@
+export default function ProjectFileManagerFixture() {
+  return (
+    <div className="admin-card">
+      <div className="admin-card-body">
+        <h3 className="admin-card-title">Soubory</h3>
+        <div
+          style={{
+            display: "flex",
+            alignItems: "center",
+            gap: "0.5rem",
+            marginBottom: "0.75rem",
+            fontSize: "0.875rem",
+            color: "var(--text-secondary)",
+          }}
+        >
+          <span>Projekt</span>
+          <span>/</span>
+          <span>Dokumentace</span>
+        </div>
+        {Array.from({ length: 4 }, (_, i) => (
+          <div
+            key={i}
+            style={{
+              display: "flex",
+              alignItems: "center",
+              gap: "0.5rem",
+              padding: "0.5rem 0",
+              borderBottom: i < 3 ? "1px solid var(--border-color)" : "none",
+            }}
+          >
+            <svg
+              width="18"
+              height="18"
+              viewBox="0 0 24 24"
+              fill="none"
+              stroke="currentColor"
+              strokeWidth="1.5"
+            >
+              <path d="M14 2H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V8z" />
+              <polyline points="14 2 14 8 20 8" />
+            </svg>
+            <span style={{ flex: 1 }}>dokument_{i + 1}.pdf</span>
+            <span
+              style={{ color: "var(--text-secondary)", fontSize: "0.8rem" }}
+            >
+              2.{i + 1} MB
+            </span>
+          </div>
+        ))}
+      </div>
+    </div>
+  );
+}