fix(mobile): hoist RN/Expo transitive deps for Metro resolution

pnpm's default strict isolation hides @babel/runtime/helpers/* and other
transitive deps from Metro, which expects flat node_modules layout.
Each missing dep was a separate failed EAS build (metro-runtime,
@babel/runtime, ...) — added .npmrc with public-hoist-pattern entries
that catch the common RN/Expo families so we stop whack-a-moling them.
Also kept @babel/runtime as direct dep of @chat-app/mobile for safety.

.npmrc

@@ -0,0 +1,15 @@
+# React Native / Expo expects a flat (npm/yarn-style) node_modules layout
+# where transitive deps are reachable from any package. pnpm's strict
+# isolation breaks that — Metro can't resolve @babel/runtime/helpers/*,
+# @expo/metro-runtime, react-native-* peers, etc. when they're only
+# installed for the package that declared them.
+#
+# These patterns hoist the common RN/Expo dependency families to the
+# workspace root node_modules so Metro and the Expo bundler can find
+# them via the standard Node resolution algorithm.
+public-hoist-pattern[]=*@babel/runtime*
+public-hoist-pattern[]=@expo/*
+public-hoist-pattern[]=expo-*
+public-hoist-pattern[]=*react-native*
+public-hoist-pattern[]=@react-native*
+public-hoist-pattern[]=*metro*

apps/mobile/package.json

@@ -18,6 +18,7 @@
     "clean": "rm -rf .expo node_modules/.cache .turbo *.tsbuildinfo"
   },
   "dependencies": {
+    "@babel/runtime": "^7.29.2",
     "@chat-app/db-types": "workspace:*",
     "@chat-app/shared": "workspace:*",
     "@config-plugins/react-native-webrtc": "^10.0.0",

pnpm-lock.yaml

@@ -150,6 +150,9 @@ importers:
 
   apps/mobile:
     dependencies:
+      '@babel/runtime':
+        specifier: ^7.29.2
+        version: 7.29.2
       '@chat-app/db-types':
         specifier: workspace:*
         version: link:../../packages/db-types