feat(security,build): add COOP/COEP headers and improve PDF viewer initialization

- Add Cross-Origin-Opener-Policy and Cross-Origin-Embedder-Policy headers to nginx.conf for enhanced security
- Create serve.json configuration file with security headers for local development
- Update npm scripts to use vite preview instead of serve package for consistency
- Fix PDF viewer file parameter handling to prevent fallback to default URL
- Enable annotation editor mode by default in PDF viewers (annotationEditorMode: 1)
- Improve PDF preference management by clearing conflicting annotation editor settings before loading
- Update iframe URL construction to use URL API for proper origin handling
- Refactor annotation viewer setup to use eventBus for stamp button activation instead of direct DOM manipulation
- Add localStorage preference configuration for signature editor and permissions in sign tool
- Enhance security posture by implementing COOP/COEP headers required for SharedArrayBuffer and cross-origin isolation

src/version.ts

@@ -0,0 +1,18 @@
+import packageJson from '../package.json';
+
+export const APP_VERSION = packageJson.version;
+
+export function injectVersion() {
+  const versionElements = document.querySelectorAll('#app-version, #app-version-simple');
+  versionElements.forEach((element) => {
+    element.textContent = APP_VERSION;
+  });
+}
+
+if (typeof document !== 'undefined') {
+  if (document.readyState === 'loading') {
+    document.addEventListener('DOMContentLoaded', injectVersion);
+  } else {
+    injectVersion();
+  }
+}