Merge main into feat/owner-carbet-crud (integrate SYS-2 schema + SYS-3 auth)

main now contains the Prisma schema (SYS-2) and NextAuth (SYS-3) that the
owner carbet CRUD depends on. Integrating them so the branch compiles and
the PR is cleanly mergeable.

- package.json: union of S3 SDK (@aws-sdk/client-s3) + auth deps.
- No source conflicts; espace-hote "Gérer mes carbets" link already in main.
- Verified: tsc --noEmit OK, next build OK (all carbet + auth routes compile).

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

src/app/api/auth/[...nextauth]/route.ts

@@ -0,0 +1,3 @@
+import { handlers } from "@/auth";
+
+export const { GET, POST } = handlers;