Add KDoc to the libraries/emoji API interfaces

Document AddRecentEmoji, GetRecentEmojis.invoke, the EmojiPickerRenderer
interface and the EmojiPickerPresenter factory, pointing at the no-op renderer
and the empty recent-emoji source so callers know how to opt out of each.

EmojiPickerPresenter itself is a Presenter and therefore out of scope.

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

libraries/emoji/api/src/main/kotlin/io/element/android/libraries/emoji/api/picker/EmojiPickerPresenter.kt

@@ -11,7 +11,14 @@ import io.element.android.libraries.architecture.Presenter
 import io.element.android.libraries.emoji.api.recentemojis.GetRecentEmojis
 
 fun interface EmojiPickerPresenter : Presenter<EmojiPickerState> {
+    /**
+     * Creates a presenter for one picker instance.
+     */
     fun interface Factory {
+        /**
+         * @param getRecentEmojis how the picker sources its recent tab; pass [io.element.android.libraries.emoji.api.recentemojis.EmptyGetRecentEmojis]
+         * for a picker that should have no recent tab at all.
+         */
         fun create(getRecentEmojis: GetRecentEmojis): EmojiPickerPresenter
     }
 }

libraries/emoji/api/src/main/kotlin/io/element/android/libraries/emoji/api/picker/EmojiPickerRenderer.kt

@@ -13,9 +13,16 @@ import androidx.compose.ui.Modifier
 import io.element.android.emojibasebindings.Emoji
 import kotlinx.collections.immutable.ImmutableSet
 
+/**
+ * Renders the emoji picker, so that callers can embed it without depending on its implementation.
+ *
+ * See [NoOpEmojiPickerRenderer] for a renderer that draws nothing, used where the picker is disabled.
+ */
 @Immutable
 interface EmojiPickerRenderer {
     /**
+     * Draws the picker.
+     *
      * @param state opaque state produced by [EmojiPickerPresenter.present].
      * @param onSelectEmoji invoked when the user taps an emoji (including a skin-tone variant).
      * @param selectedEmojis emojis to visually mark as already selected.

libraries/emoji/api/src/main/kotlin/io/element/android/libraries/emoji/api/recentemojis/AddRecentEmoji.kt

@@ -8,6 +8,12 @@
 
 package io.element.android.libraries.emoji.api.recentemojis
 
+/**
+ * Records that an emoji was just used, so it surfaces in the picker's recent list; see [GetRecentEmojis] for the read side.
+ */
 fun interface AddRecentEmoji {
+    /**
+     * @param emoji the emoji that was just used, as its unicode representation.
+     */
     suspend operator fun invoke(emoji: String): Result<Unit>
 }

libraries/emoji/api/src/main/kotlin/io/element/android/libraries/emoji/api/recentemojis/GetRecentEmojis.kt

@@ -15,6 +15,7 @@ import kotlinx.collections.immutable.persistentListOf
  * Returns the list of recently used emojis for reactions.
  */
 fun interface GetRecentEmojis {
+    /** Returns the recently used emojis, most recent first; see [EmptyGetRecentEmojis] for a picker with no recent tab. */
     suspend operator fun invoke(): Result<ImmutableList<String>>
 }