chore(guide): remove decommissioned QDS_ADMIN role reference (dead code)

QDS_ADMIN was removed from the hiveops-auth Role enum (972a28a); no JWT can carry
ROLE_QDS_ADMIN. Strip the stale SecurityConfig hasAnyRole entry. Zero runtime change.

Refs hiveiq-src/hiveops-incident#253

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/src/main/java/com/hiveops/guide/config/SecurityConfig.java

@@ -37,7 +37,7 @@ public class SecurityConfig {
                         .requestMatchers("/actuator/health", "/error").permitAll()
                         // Read-only guide API: any authenticated user (audience gating done in the controller)
                         .requestMatchers(HttpMethod.GET, "/api/v1/guide/**")
-                            .hasAnyRole("USER", "CUSTOMER", "ADMIN", "MSP_ADMIN", "QDS_ADMIN", "BCOS_ADMIN")
+                            .hasAnyRole("USER", "CUSTOMER", "ADMIN", "MSP_ADMIN", "BCOS_ADMIN")
                         .anyRequest().authenticated()
                 )
                 .addFilterBefore(jwtAuthenticationFilter, UsernamePasswordAuthenticationFilter.class);