feat(chat): group chat contract and service layer

apps/flipcash/shared/featureflags/src/main/kotlin/com/flipcash/app/featureflags/FeatureFlag.kt

@@ -117,6 +117,15 @@ sealed interface FeatureFlag<T: Any> {
         override val persistLogOut: Boolean = false
     }
 
+    @FeatureFlagMarker
+    data object GroupChats: FeatureFlag<Boolean> {
+        override val key: String = "group_chats_enabled"
+        override val default: Boolean = false
+        override val launched: Boolean = false
+        override val visible: Boolean = true
+        override val persistLogOut: Boolean = false
+    }
+
     companion object {
         val entries: List<FeatureFlag<*>>
             get() = FeatureFlagEntries.entries
@@ -139,6 +148,7 @@ val FeatureFlag<*>.title: String
         FeatureFlag.ContactPickerMode -> "Contact Picker Mode"
         FeatureFlag.ShowNetworkState -> "Network Offline Indicator"
         FeatureFlag.FrostedTipCard -> "Frosted Tip Card"
+        FeatureFlag.GroupChats -> "Group Chats"
     }
 
 val FeatureFlag<*>.message: String
@@ -152,6 +162,7 @@ val FeatureFlag<*>.message: String
         FeatureFlag.ContactPickerMode -> "When enabled, contacts will be accessed via the system contact picker instead of requesting full READ_CONTACTS permission"
         FeatureFlag.ShowNetworkState -> "When enabled, you'll gain the ability to see the network state on the Scanner when offline"
         FeatureFlag.FrostedTipCard -> "When enabled, the tip card in the scanner renders as frosted glass over a blurred snapshot of the camera instead of a solid card"
+        FeatureFlag.GroupChats -> "When enabled, group chats appear in your chat list alongside your direct messages"
     }