feat(ui): Add feature flag system (#208)

ui/src/providers/FeatureFlagProvider.tsx

@@ -0,0 +1,42 @@
+import { createContext } from "react";
+import semver from "semver";
+
+interface FeatureFlagContextType {
+  appVersion: string | null;
+  isFeatureEnabled: (minVersion: string) => boolean;
+}
+
+// Create the context
+export const FeatureFlagContext = createContext<FeatureFlagContextType>({
+  appVersion: null,
+  isFeatureEnabled: () => false,
+});
+
+// Provider component that fetches version and provides context
+export const FeatureFlagProvider = ({
+  children,
+  appVersion,
+}: {
+  children: React.ReactNode;
+  appVersion: string | null;
+}) => {
+  const isFeatureEnabled = (minAppVersion: string) => {
+    // If no version is set, feature is disabled.
+    // The feature flag component can deside what to display as a fallback - either omit the component or like a "please upgrade to enable".
+    if (!appVersion) return false;
+
+    // Extract the base versions without prerelease identifier
+    const baseCurrentVersion = semver.coerce(appVersion)?.version;
+    const baseMinVersion = semver.coerce(minAppVersion)?.version;
+
+    if (!baseCurrentVersion || !baseMinVersion) return false;
+
+    return semver.gte(baseCurrentVersion, baseMinVersion);
+  };
+
+  const value = { appVersion, isFeatureEnabled };
+
+  return (
+    <FeatureFlagContext.Provider value={value}>{children}</FeatureFlagContext.Provider>
+  );
+};