chore: bump version to 1.6.4 (versionCode 16)

Includes Expo SDK 54 patch alignment from #87.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app.json

@@ -2,7 +2,7 @@
   "expo": {
     "name": "Simpl-Liste",
     "slug": "simpl-liste",
-    "version": "1.6.3",
+    "version": "1.6.4",
     "orientation": "portrait",
     "icon": "./assets/images/icon.png",
     "scheme": "simplliste",
@@ -24,7 +24,7 @@
         "backgroundColor": "#FFF8F0"
       },
       "edgeToEdgeEnabled": true,
-      "versionCode": 15
+      "versionCode": 16
     },
     "plugins": [
       "expo-router",

package.json

@@ -1,7 +1,7 @@
 {
   "name": "simpl-liste",
   "main": "index.js",
-  "version": "1.6.3",
+  "version": "1.6.4",
   "scripts": {
     "start": "expo start",
     "test": "node tests/smoke.test.cjs",