fix(auth): stop wiki login loop to coming-soon and surface non-member state

Members (and pre-registrants) hitting wiki.ghostguild.org were getting bounced
to /coming-soon with a "Pre-Register" link, even when the OIDC flow was
working correctly.

- Allowlist /auth/oidc-error, /auth/logout-confirm, /auth/logout-success,
  and /verify in the coming-soon middleware so OIDC errors and main-site
  magic links stop redirecting to the pre-register page.
- Raise OIDC Interaction TTL from 10m to 15m so it outlives the magic-link
  JWT and legitimate members don't hit expired-interaction errors when they
  click the email a few minutes late.
- Differentiate the "email isn't a registered member" response on the wiki
  login route and show a dedicated "Not a member yet" state with a
  pre-register link and contact email, instead of the misleading
  "Check your inbox" that silently failed.

app/middleware/coming-soon.global.js

@@ -12,6 +12,10 @@ export default defineNuxtRouteMiddleware(async (to, from) => {
   if (
     to.path === "/coming-soon" ||
     to.path === "/auth/wiki-login" ||
+    to.path === "/auth/oidc-error" ||
+    to.path === "/auth/logout-confirm" ||
+    to.path === "/auth/logout-success" ||
+    to.path === "/verify" ||
     to.path.startsWith("/admin")
   ) {
     return;