fix(auth): handle prerender hydration auth state

[onmax]

Summary

• remove middleware hydration bypass for auth-protected routes so guest/user checks still run
• keep public routes unaffected when no auth rule is resolved
• keep \ false during prerender hydration when SSR auth snapshot is empty
• add focused regression tests for middleware route-rule auth handling and prerender readiness timing

Tests

• 
  RUN v4.0.15 /Users/maxi/nuxt/better-auth

✓ |unit| test/auth-global-middleware.test.ts (3 tests) 17ms
✓ |unit| test/use-user-session.test.ts (36 tests) 5049ms
✓ signUp does not auto-navigate to authenticated redirect when session is unresolved 5002ms

Test Files 2 passed (2)
Tests 39 passed (39)
Start at 17:53:40
Duration 5.22s (transform 103ms, setup 0ms, import 167ms, tests 5.07s, environment 0ms)

• \

@onmax/nuxt-better-auth@0.0.2-alpha.29 lint /Users/maxi/nuxt/better-auth
eslint .

• \

@onmax/nuxt-better-auth@0.0.2-alpha.29 typecheck /Users/maxi/nuxt/better-auth
vue-tsc --noEmit

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/nuxt-modules/better-auth/@onmax/nuxt-better-auth@186

commit: 7e3569d