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

package.json

@@ -16,10 +16,12 @@
     "test:watch": "vitest watch",
     "build:docker": "vite build",
     "format": "prettier --write .",
+    "update-version": "node scripts/update-version.js",
     "release": "node scripts/release.js patch",
     "release:minor": "node scripts/release.js minor",
     "release:major": "node scripts/release.js major",
-    "serve:simple": "SIMPLE_MODE=true npm run build && npx serve dist -p 3000",
+    "serve:simple": "SIMPLE_MODE=true npm run build && npm run preview -- --port 3000",
+    "serve": "npm run build && npm run preview -- --port 3000",
     "package": "node scripts/package-dist.js"
   },
   "devDependencies": {