Add contributing guidelines, feature flag utilities, and route integrity tests

frontend/src/config/featureFlags.ts

@@ -0,0 +1,23 @@
+/**
+ * Feature flag utilities for the frontend.
+ *
+ * Feature flags are read from VITE_FEATURE_* environment variables.
+ * When a flag is absent or set to "true", the feature is ENABLED (opt-out model).
+ * Set a flag to "false" to disable a feature.
+ *
+ * Usage:
+ *   import { isFeatureEnabled } from '@/config/featureFlags';
+ *   if (isFeatureEnabled('EDITOR')) { ... }
+ */
+
+type FeatureName = 'EDITOR' | 'OCR' | 'REMOVEBG';
+
+/**
+ * Check whether a feature is enabled.
+ * Defaults to `true` if the env var is not set.
+ */
+export function isFeatureEnabled(feature: FeatureName): boolean {
+  const value = import.meta.env[`VITE_FEATURE_${feature}`];
+  if (value === undefined || value === '') return true; // enabled by default
+  return value.toLowerCase() !== 'false';
+}