fix: pin react to 19.2.3 to match react-native-renderer

react-native@0.85.3 bundles react-native-renderer@19.2.3. Having
react@19.2.7 in package.json caused a version mismatch error at
runtime ("Incompatible React versions") that killed the process
before any JS could render, appearing as a native crash.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -19,7 +19,7 @@
     "expo-sqlite": "~56.0.5",
     "expo-status-bar": "~56.0.4",
     "nativewind": "~4.2.5",
-    "react": "19.2.7",
+    "react": "19.2.3",
     "react-native": "0.85.3",
     "react-native-gesture-handler": "~3.0.2",
     "react-native-reanimated": "~4.4.1",