feat: add modal component for sighting details with content display

- Implemented ModalComponent for reusable modal functionality.
- Created SightingItemModal to manage modal state and display sighting details.
- Developed SightingModalContent to render sighting information including video feed and metadata.

package.json

@@ -22,6 +22,7 @@
     "react": "^19.2.0",
     "react-dom": "^19.2.0",
     "react-konva": "^19.2.1",
+    "react-modal": "^3.16.3",
     "tailwindcss": "^4.1.18"
   },
   "devDependencies": {
@@ -30,6 +31,7 @@
     "@types/node": "^24.10.1",
     "@types/react": "^19.2.5",
     "@types/react-dom": "^19.2.3",
+    "@types/react-modal": "^3.16.3",
     "@vitejs/plugin-react": "^5.1.1",
     "eslint": "^9.39.1",
     "eslint-plugin-react-hooks": "^7.0.1",