feat: shop buy, forum replies, tickets, messages, sessions, and UX hardening

Complete remaining product gaps: credit-based shop purchases, guild thread replies, help ticket detail/reply/close, offline message compose, sign-out-everywhere via JWT version, ads delete confirm, soft-fail feedback, rate limits, loading states, and single auth() in site layout.

Co-authored-by: Cursor <[email protected]>

src/app/(site)/help/tickets/loading.tsx

@@ -0,0 +1 @@
+export { default } from "../../friends/loading";