fix: move leaflet from devDependencies to dependencies

Consumers need leaflet at runtime since it is imported by the
bundled output.

package.json

@@ -25,10 +25,11 @@
   "author": "buddy",
   "license": "MIT",
   "type": "module",
-  "dependencies": {},
+  "dependencies": {
+    "leaflet": "1.9.4"
+  },
   "devDependencies": {
     "@types/leaflet": "1.9.21",
-    "leaflet": "1.9.4",
     "@typescript-eslint/eslint-plugin": "8.60.1",
     "@typescript-eslint/parser": "8.60.1",
     "esbuild": "^0.28.0",