fix(mobile): correct dark-mode config, pin native builds to production

userInterfaceStyle was hardcoded to "light" in app.json — since the app
resolves its "Automatic" theme option via RN's useColorScheme(), which
Expo only wires up to the OS when userInterfaceStyle is "automatic",
the auto setting would have silently never followed the system theme
in a real native build (only worked in the dev client, which isn't
gated by this app.json field the same way).

Also pin the preview/production EAS build profiles' EXPO_PUBLIC_* env
vars explicitly in eas.json. .env is gitignored, so a cloud build has
no guarantee of seeing it (or seeing the right values) — this makes
the native build's API/Clerk/Supabase targets explicit and independent
of whatever's in the local .env at build time. Values are non-secret
(EXPO_PUBLIC_* is always inlined into the client bundle).

mobile/app.json

@@ -6,7 +6,7 @@
     "version": "1.0.0",
     "orientation": "portrait",
     "icon": "./assets/icon.png",
-    "userInterfaceStyle": "light",
+    "userInterfaceStyle": "automatic",
     "newArchEnabled": true,
     "ios": {
       "supportsTablet": true,

mobile/eas.json

@@ -9,9 +9,20 @@
       "distribution": "internal"
     },
     "preview": {
-      "distribution": "internal"
+      "distribution": "internal",
+      "env": {
+        "EXPO_PUBLIC_API_URL": "https://pawfeed.org",
+        "EXPO_PUBLIC_CLERK_PUBLISHABLE_KEY": "pk_live_Y2xlcmsucGF3ZmVlZC5vcmck",
+        "EXPO_PUBLIC_SUPABASE_URL": "https://gqhsovpcfgffdtjxumyy.supabase.co"
+      }
     },
-    "production": {}
+    "production": {
+      "env": {
+        "EXPO_PUBLIC_API_URL": "https://pawfeed.org",
+        "EXPO_PUBLIC_CLERK_PUBLISHABLE_KEY": "pk_live_Y2xlcmsucGF3ZmVlZC5vcmck",
+        "EXPO_PUBLIC_SUPABASE_URL": "https://gqhsovpcfgffdtjxumyy.supabase.co"
+      }
+    }
   },
   "submit": {
     "production": {}