In app/api/projects/[id]/export/route.ts, derive the current user from the verified Supabase server session and load the project by both project ID and owner ID. Return 404 for missing or cross-user records, keep error messages generic, and do not trust a user ID from the request. Add integration tests for owner success, unauthenticated access, cross-user access, and a deleted project. Preserve the current export format and provide a reviewable diff.

Add a durable Stripe event ledger keyed by event.id and process checkout/subscription events in one database transaction. Treat duplicate delivery as success without repeating entitlement changes. Check every database result and return non-2xx when durable processing fails so Stripe retries. Add tests for duplicate, concurrent, out-of-order, invalid-signature, and database-failure deliveries. Do not weaken raw-body signature verification.

Replace the callback's unrestricted next parameter with an allow-list of relative application paths. Reject absolute URLs, protocol-relative URLs, encoded bypasses, and backslash variants. Keep /dashboard and /settings/account as valid destinations, default safely when invalid, and add table-driven tests for accepted and rejected redirects.

Refactor account deletion into an authenticated, auditable server workflow that derives the user ID from the current session, records progress, and does not report success while Stripe cancellation or required database updates are unresolved. Make retries idempotent and add tests for unauthenticated, cross-user, partial-provider-failure, retry, and successful completion paths.

Update the project search effect to cancel superseded requests with AbortController, ignore AbortError, and prevent older responses from overwriting the current query. Preserve the last valid result during refresh and add tests with deferred promises for rapid query changes and component unmount.