chore(frontend): add @types/geojson dependency

Add GeoJSON type definitions for TypeScript support.

- Add @types/geojson package dependency
- Add 'geojson' to tsconfig types array

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

frontend/package.json

@@ -27,6 +27,7 @@
 		"@sveltejs/kit": "^2.22.0",
 		"@sveltejs/vite-plugin-svelte": "^6.2.4",
 		"@tailwindcss/vite": "^4.2.0",
+		"@types/geojson": "^7946.0.16",
 		"@types/node": "^22.19.11",
 		"bits-ui": "^2.16.1",
 		"clsx": "^2.1.1",

frontend/tsconfig.json

@@ -9,7 +9,8 @@
 		"skipLibCheck": true,
 		"sourceMap": true,
 		"strict": true,
-		"moduleResolution": "bundler"
+		"moduleResolution": "bundler",
+		"types": ["geojson"]
 	}
 	// Path aliases are handled by https://svelte.dev/docs/kit/configuration#alias
 	// except $lib which is handled by https://svelte.dev/docs/kit/configuration#files