test: strengthen safety-critical coverage

src/main/config-store.cjs

@@ -109,7 +109,7 @@ class ConfigStore {
         })]))
         : {},
       deploymentStates: source.deploymentStates && typeof source.deploymentStates === 'object' ? source.deploymentStates : {},
-      favorites: uniqueStrings(source.favorites).map((item) => item.toLowerCase()),
+      favorites: [...new Set(uniqueStrings(source.favorites).map((item) => item.toLowerCase()))],
       updates: { ...DEFAULT_CONFIG.updates, ...(source.updates || {}) },
       servers: Array.isArray(source.servers) ? source.servers.filter((item) => item && typeof item === 'object') : [],
       preferences: { ...DEFAULT_CONFIG.preferences, ...(source.preferences || {}) },