feat: add v1 users API routes for backward compatibility

- Add /api/v1/users path routing to users service in gateway
- Add v1_router() in auth.rs with resend-otp endpoint
- Nest /api/v1/users route in main.rs
- Support legacy /api/v1/users/resend-otp endpoint

apps/gateway/src/main.rs

@@ -84,6 +84,7 @@ impl Services {
         // Auth, users, roles, notifications, runtime-config, config, KB, support
         if path.starts_with("/api/auth")
             || path.starts_with("/api/users")
+            || path.starts_with("/api/v1/users")
             || path.starts_with("/api/me")
             || path.starts_with("/api/profile")
             || path.starts_with("/api/onboarding")

apps/users/src/handlers/auth.rs

@@ -724,3 +724,10 @@ async fn switch_role(
         "expires_in":   900
     }))))
 }
+
+// ── V1 API Router (for backward compatibility) ─────────────────────────
+
+pub fn v1_router() -> Router<AppState> {
+    Router::new()
+        .route("/resend-otp", post(resend_otp))
+}

apps/users/src/main.rs

@@ -54,6 +54,8 @@ async fn main() {
     let app = Router::new()
         // ── Auth ─────────────────────────────────────────────────────────
         .nest("/api/auth", handlers::auth::router())
+        // ── V1 API (backward compatibility) ───────────────────────────────
+        .nest("/api/v1/users", handlers::auth::v1_router())
         // ── Roles & User Self-Service ─────────────────────────────────────
         .nest("/api/admin/roles", handlers::roles::router())
         .nest("/api/admin/permissions", handlers::permissions::router())