fix: move email-in-address endpoint from /auth to /api/v1 prefix

The GET /me/email-in-address endpoint was unreachable because the Gateway
HTTPRoute routes all /auth/* traffic to Better-Auth (port 3001), not the
API service. This change:
- Moves the endpoint from the /auth router to a new /api/v1/me/ router
- Adds EmailInAddressResponse schema and get_email_in_address service method
- Updates Settings.tsx to call /api/v1/me/email-in-address

Fixes CAR-445.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/pages/Settings.tsx

@@ -15,7 +15,7 @@ export function Settings() {
 
   useEffect(() => {
     if (!session?.user) return
-    fetch('/auth/me/email-in-address', {
+    fetch('/api/v1/me/email-in-address', {
       credentials: 'include',
     })
       .then((res) => res.json())