feat(message-input): add search box to slash-command popups

Both the inline autocomplete (triggered by `/` in the textarea) and the
dropdown popup (triggered by the slash-command button) now show a search
field at the top. Matching uses substring on name and description, and
ranks name matches above description/id-only matches.

src/i18n/messages/ar.json

@@ -1573,7 +1573,9 @@
         "forkAndSend": "تفريع وإرسال",
         "slashCommands": "أوامر الشرطة المائلة",
         "expertSkills": "مهارات الخبراء",
-        "expertsEmptyForAgent": "لا يحتوي هذا العميل على خبراء مفعّلين. فعّلهم من الإعدادات > الخبراء."
+        "expertsEmptyForAgent": "لا يحتوي هذا العميل على خبراء مفعّلين. فعّلهم من الإعدادات > الخبراء.",
+        "slashSearchPlaceholder": "البحث عن الأوامر...",
+        "slashSearchEmpty": "لا توجد أوامر مطابقة"
       },
       "messageQueue": {
         "addToQueue": "إضافة للقائمة",

src/i18n/messages/de.json

@@ -1573,7 +1573,9 @@
         "forkAndSend": "Fork & Senden",
         "slashCommands": "Slash-Befehle",
         "expertSkills": "Expertenfähigkeiten",
-        "expertsEmptyForAgent": "Dieser Agent hat keine aktivierten Experten. Aktivieren Sie sie unter Einstellungen > Experten."
+        "expertsEmptyForAgent": "Dieser Agent hat keine aktivierten Experten. Aktivieren Sie sie unter Einstellungen > Experten.",
+        "slashSearchPlaceholder": "Befehle suchen...",
+        "slashSearchEmpty": "Keine passenden Befehle"
       },
       "messageQueue": {
         "addToQueue": "Zur Warteschlange",

src/i18n/messages/en.json

@@ -1573,7 +1573,9 @@
         "forkAndSend": "Fork & Send",
         "slashCommands": "Slash commands",
         "expertSkills": "Expert skills",
-        "expertsEmptyForAgent": "This agent has no enabled experts. Enable them in Settings > Experts."
+        "expertsEmptyForAgent": "This agent has no enabled experts. Enable them in Settings > Experts.",
+        "slashSearchPlaceholder": "Search commands...",
+        "slashSearchEmpty": "No matching commands"
       },
       "messageQueue": {
         "addToQueue": "Queue message",

src/i18n/messages/es.json

@@ -1573,7 +1573,9 @@
         "forkAndSend": "Fork y Enviar",
         "slashCommands": "Comandos de barra",
         "expertSkills": "Habilidades de expertos",
-        "expertsEmptyForAgent": "Este agente no tiene expertos habilitados. Actívalos en Configuración > Expertos."
+        "expertsEmptyForAgent": "Este agente no tiene expertos habilitados. Actívalos en Configuración > Expertos.",
+        "slashSearchPlaceholder": "Buscar comandos...",
+        "slashSearchEmpty": "Sin comandos coincidentes"
       },
       "messageQueue": {
         "addToQueue": "Agregar a la cola",

src/i18n/messages/fr.json

@@ -1573,7 +1573,9 @@
         "forkAndSend": "Fork & Envoyer",
         "slashCommands": "Commandes slash",
         "expertSkills": "Compétences d'expert",
-        "expertsEmptyForAgent": "Cet agent n'a aucun expert activé. Activez-les dans Paramètres > Experts."
+        "expertsEmptyForAgent": "Cet agent n'a aucun expert activé. Activez-les dans Paramètres > Experts.",
+        "slashSearchPlaceholder": "Rechercher des commandes...",
+        "slashSearchEmpty": "Aucune commande correspondante"
       },
       "messageQueue": {
         "addToQueue": "Mettre en file",

src/i18n/messages/ja.json

@@ -1573,7 +1573,9 @@
         "forkAndSend": "フォークして送信",
         "slashCommands": "スラッシュコマンド",
         "expertSkills": "エキスパートスキル",
-        "expertsEmptyForAgent": "このエージェントで有効なエキスパートはありません。「設定 > エキスパート」から有効にしてください。"
+        "expertsEmptyForAgent": "このエージェントで有効なエキスパートはありません。「設定 > エキスパート」から有効にしてください。",
+        "slashSearchPlaceholder": "コマンドを検索...",
+        "slashSearchEmpty": "一致するコマンドがありません"
       },
       "messageQueue": {
         "addToQueue": "キューに追加",

src/i18n/messages/ko.json

@@ -1573,7 +1573,9 @@
         "forkAndSend": "포크 & 전송",
         "slashCommands": "슬래시 명령",
         "expertSkills": "전문가 스킬",
-        "expertsEmptyForAgent": "이 에이전트에 활성화된 전문가가 없습니다. 설정 > 전문가에서 활성화하세요."
+        "expertsEmptyForAgent": "이 에이전트에 활성화된 전문가가 없습니다. 설정 > 전문가에서 활성화하세요.",
+        "slashSearchPlaceholder": "명령 검색...",
+        "slashSearchEmpty": "일치하는 명령이 없습니다"
       },
       "messageQueue": {
         "addToQueue": "대기열에 추가",

src/i18n/messages/pt.json

@@ -1573,7 +1573,9 @@
         "forkAndSend": "Fork & Enviar",
         "slashCommands": "Comandos de barra",
         "expertSkills": "Habilidades de especialistas",
-        "expertsEmptyForAgent": "Este agente não tem especialistas ativados. Ative-os em Configurações > Especialistas."
+        "expertsEmptyForAgent": "Este agente não tem especialistas ativados. Ative-os em Configurações > Especialistas.",
+        "slashSearchPlaceholder": "Buscar comandos...",
+        "slashSearchEmpty": "Nenhum comando correspondente"
       },
       "messageQueue": {
         "addToQueue": "Adicionar à fila",

src/i18n/messages/zh-CN.json

@@ -1573,7 +1573,9 @@
         "forkAndSend": "分叉发送",
         "slashCommands": "斜杠命令",
         "expertSkills": "专家技能",
-        "expertsEmptyForAgent": "该智能体没有启用任何专家。请在「设置 > 专家」中启用。"
+        "expertsEmptyForAgent": "该智能体没有启用任何专家。请在「设置 > 专家」中启用。",
+        "slashSearchPlaceholder": "搜索命令...",
+        "slashSearchEmpty": "没有匹配的命令"
       },
       "messageQueue": {
         "addToQueue": "加入队列",

src/i18n/messages/zh-TW.json

@@ -1573,7 +1573,9 @@
         "forkAndSend": "分叉發送",
         "slashCommands": "斜線命令",
         "expertSkills": "專家技能",
-        "expertsEmptyForAgent": "該智慧代理沒有啟用任何專家。請在「設定 > 專家」中啟用。"
+        "expertsEmptyForAgent": "該智慧代理沒有啟用任何專家。請在「設定 > 專家」中啟用。",
+        "slashSearchPlaceholder": "搜尋命令...",
+        "slashSearchEmpty": "沒有符合的指令"
       },
       "messageQueue": {
         "addToQueue": "加入佇列",