Add KDoc to the features/leaveroom API interfaces

Document LeaveRoomState, LeaveRoomEvent and LeaveRoomRenderer.

The renderer doc records the two things a host screen needs to know, both taken
from LeaveRoomPresenter and LeaveRoomView: it draws nothing until a leave event is
sent, and onSelectNewOwners fires specifically when the user is the last owner of
a room that still has other members.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

features/leaveroom/api/src/main/kotlin/io/element/android/features/leaveroom/api/LeaveRoomEvent.kt

@@ -10,6 +10,9 @@ package io.element.android.features.leaveroom.api
 
 import io.element.android.libraries.matrix.api.core.RoomId
 
+/**
+ * Events sent to the leave room presenter through [LeaveRoomState.eventSink].
+ */
 interface LeaveRoomEvent {
     data class LeaveRoom(val roomId: RoomId, val needsConfirmation: Boolean) : LeaveRoomEvent
 }

features/leaveroom/api/src/main/kotlin/io/element/android/features/leaveroom/api/LeaveRoomRenderer.kt

@@ -12,7 +12,17 @@ import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
 import io.element.android.libraries.matrix.api.core.RoomId
 
+/**
+ * Renders the confirmation dialogs of the leave room flow; it draws nothing until the host screen sends a leave event.
+ */
 fun interface LeaveRoomRenderer {
+    /**
+     * Draws whichever dialog the current state calls for.
+     *
+     * @param state the state produced by the leave room presenter.
+     * @param onSelectNewOwners called when the user is the last owner of a room that still has other members, and must promote someone before leaving.
+     * @param modifier layout modifier for the container.
+     */
     @Composable
     fun Render(
         state: LeaveRoomState,

features/leaveroom/api/src/main/kotlin/io/element/android/features/leaveroom/api/LeaveRoomState.kt

@@ -10,7 +10,11 @@ package io.element.android.features.leaveroom.api
 
 import androidx.compose.runtime.Immutable
 
+/**
+ * State of the leave room flow, which is only the confirmation dialogs: the screen it is hosted in owns the rest of the UI.
+ */
 @Immutable
 interface LeaveRoomState {
+    /** Where the host screen sends its events to start or confirm leaving a room. */
     val eventSink: (LeaveRoomEvent) -> Unit
 }