Add threaded messaging feature flag

src/i18n/strings/en_EN.json

@@ -808,6 +808,7 @@
     "Render LaTeX maths in messages": "Render LaTeX maths in messages",
     "Communities v2 prototypes. Requires compatible homeserver. Highly experimental - use with caution.": "Communities v2 prototypes. Requires compatible homeserver. Highly experimental - use with caution.",
     "Message Pinning": "Message Pinning",
+    "Threaded messaging": "Threaded messaging",
     "Custom user status messages": "Custom user status messages",
     "Group & filter rooms by custom tags (refresh to apply changes)": "Group & filter rooms by custom tags (refresh to apply changes)",
     "Render simple counters in room header": "Render simple counters in room header",

src/settings/Settings.tsx

@@ -239,6 +239,12 @@ export const SETTINGS: {[setting: string]: ISetting} = {
         supportedLevels: LEVELS_FEATURE,
         default: false,
     },
+    "feature_threading": {
+        isFeature: true,
+        displayName: _td("Threaded messaging"),
+        supportedLevels: LEVELS_FEATURE,
+        default: false,
+    },
     "feature_custom_status": {
         isFeature: true,
         displayName: _td("Custom user status messages"),