refactor: remove all JWT-related code and references

JWT was never used - auth uses X-User-Id header. Removes jwt.ts utility,
jsonwebtoken dependency, stubbed refresh/logout endpoints, and updates
all docs (PUML diagrams, api-routes, tex, CLAUDE.md) accordingly.

apps/server/src/routes/auth.routes.ts

@@ -6,8 +6,6 @@ export function createAuthRoutes(authController: AuthController): Router {
 
   router.post("/login", (req, res) => authController.login(req, res));
   router.post("/register", (req, res) => authController.register(req, res));
-  router.post("/refresh", (req, res) => authController.refresh(req, res));
-  router.post("/logout", (req, res) => authController.logout(req, res));
 
   return router;
 }