feat(auth): add cold-start token verification with loading state to app layout

Move token verification from root layout SessionGate to (app) group layout,
enabling cold-start verification without blocking public pages (privacy/terms).
Show ActivityIndicator while verification is in progress, then redirect to
login if unverified.

BREAKING CHANGE: Authentication flow changed - token verification now occurs
in the (app) layout group instead of root layout SessionGate wrapper.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "with_you",
-  "version": "0.0.2",
+  "version": "1.0.0",
   "main": "expo-router/entry",
   "scripts": {
     "start": "expo start",