fix: redirect unauthenticated users from subscriptions page

[FaisalMisbah23]

Summary

Fix unauthenticated access handling for the subscriptions page.

Previously, a logged-out user could navigate directly to /subscriptions. The page would render and then display an authentication error after a subscription-related API request returned 401.

This change adds an authentication check at the subscriptions layout level using getUserFromAuthOrRedirect(), ensuring unauthenticated users are redirected before subscription content is rendered.

Fixes #4136

Verification

• Logged out and attempted to access /subscriptions
• Confirmed unauthenticated users are redirected instead of seeing the authentication error
• Added test coverage for the subscriptions layout authentication requirement

Visual Changes

N/A

Reviewer Notes

This change applies the authentication guard at the layout level so all routes under /subscriptions require authentication before rendering.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (2 files)

• apps/web/src/app/(app)/subscriptions/layout.tsx
• apps/web/src/app/(app)/subscriptions/layout.test.tsx

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