feat(chat): emoji picker as an in-pane overlay with keyword search

Reworked the emoji picker from a floating popup (which overlapped the message
area) into an overlay that takes over the conversation-list pane while open:
a Cancel button + a keyword search box at the top, then a responsive grid below
that wraps to the pane width.

Each emoji now carries search keywords (grin/heart/fire/…) so the search box
filters the ~150-emoji set. The 🙂 composer button toggles the overlay;
selecting an emoji appends it to the composer (byte-cap respected) and the
overlay stays open for multiple picks.

+1 CJK glyph (絵) for the ja "Search emoji" string.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

res/lang/de.json

@@ -139,6 +139,7 @@
     "chat_cancel": "Abbrechen",
     "chat_contact_added": "Kontakt hinzugefügt – benenne ihn in Kontakte um",
     "chat_contact_request": "kontaktanfrage",
+    "chat_emoji_search": "Emoji suchen",
     "chat_empty_hint": "Noch keine Unterhaltungen. Nachrichten, die du erhältst, erscheinen hier.",
     "chat_empty_start": "Starte eine mit \"Neue Unterhaltung\".",
     "chat_empty_title": "Noch keine Unterhaltungen",

res/lang/es.json

@@ -139,6 +139,7 @@
     "chat_cancel": "Cancelar",
     "chat_contact_added": "Contacto añadido: renómbralo en Contactos",
     "chat_contact_request": "solicitud de contacto",
+    "chat_emoji_search": "Buscar emoji",
     "chat_empty_hint": "Aún no hay conversaciones. Los mensajes que recibas aparecerán aquí.",
     "chat_empty_start": "Inicia una con \"Nueva conversación\".",
     "chat_empty_title": "Aún no hay conversaciones",

res/lang/fr.json

@@ -139,6 +139,7 @@
     "chat_cancel": "Annuler",
     "chat_contact_added": "Contact ajouté — renommez-le dans Contacts",
     "chat_contact_request": "demande de contact",
+    "chat_emoji_search": "Rechercher un emoji",
     "chat_empty_hint": "Aucune conversation pour l'instant. Les messages que vous recevez apparaîtront ici.",
     "chat_empty_start": "Commencez-en une avec « Nouvelle conversation ».",
     "chat_empty_title": "Aucune conversation pour l'instant",

res/lang/ja.json

@@ -139,6 +139,7 @@
     "chat_cancel": "キャンセル",
     "chat_contact_added": "連絡先を追加しました — 連絡先で名前を変更できます",
     "chat_contact_request": "連絡リクエスト",
+    "chat_emoji_search": "絵文字を検索",
     "chat_empty_hint": "まだ会話はありません。受信したメッセージはここに表示されます。",
     "chat_empty_start": "「新しい会話」から始めましょう。",
     "chat_empty_title": "会話はまだありません",

res/lang/ko.json

@@ -139,6 +139,7 @@
     "chat_cancel": "취소",
     "chat_contact_added": "연락처 추가됨 — 연락처에서 이름을 변경하세요",
     "chat_contact_request": "연락 요청",
+    "chat_emoji_search": "이모지 검색",
     "chat_empty_hint": "아직 대화가 없습니다. 받은 메시지가 여기에 표시됩니다.",
     "chat_empty_start": "\"새 대화\"로 시작하세요.",
     "chat_empty_title": "아직 대화가 없습니다",

res/lang/pt.json

@@ -139,6 +139,7 @@
     "chat_cancel": "Cancelar",
     "chat_contact_added": "Contato adicionado — renomeie em Contatos",
     "chat_contact_request": "solicitação de contato",
+    "chat_emoji_search": "Pesquisar emoji",
     "chat_empty_hint": "Nenhuma conversa ainda. As mensagens que você receber aparecerão aqui.",
     "chat_empty_start": "Inicie uma com \"Nova conversa\".",
     "chat_empty_title": "Ainda não há conversas",

res/lang/ru.json

@@ -139,6 +139,7 @@
     "chat_cancel": "Отмена",
     "chat_contact_added": "Контакт добавлен — переименуйте его в Контактах",
     "chat_contact_request": "запрос контакта",
+    "chat_emoji_search": "Поиск эмодзи",
     "chat_empty_hint": "Пока нет переписок. Полученные сообщения появятся здесь.",
     "chat_empty_start": "Начните новый с помощью «Новый разговор».",
     "chat_empty_title": "Пока нет разговоров",

res/lang/zh.json

@@ -139,6 +139,7 @@
     "chat_cancel": "取消",
     "chat_contact_added": "已添加联系人——可在联系人中重命名",
     "chat_contact_request": "联系人请求",
+    "chat_emoji_search": "搜索表情",
     "chat_empty_hint": "暂无对话。您收到的消息将显示在此处。",
     "chat_empty_start": "点击\"新建会话\"开始。",
     "chat_empty_title": "还没有会话",