feat: 消息气泡长文字支持「展开全部/收起全部」折叠

- 新增 CollapsibleText 组件：超过 8 行文字自动折叠，按行高对齐裁切，底部柔和渐隐遮罩暗示有更多内容
- 折叠按钮左对齐，胶囊样式 + chevron 图标，hover 浅背景高亮，点击 chevron 旋转 180°
- 应用到全部 5 种气泡：Text/ImageWithText/Album/Video/FileDoc
- 动画统一使用 motion 包的 EASE_OUT 缓动，尊重 reducedMotion=user
- i18n 七种语言新增 showMore/showLess 文案

src/i18n.tsx

@@ -45,6 +45,8 @@ const zhDict: Dict = {
   downloading: "下载中…",
   downloadOk: "下载完成",
   downloadFail: "下载失败，请重试",
+  showMore: "展开全部",
+  showLess: "收起全部",
   share: "分享",
   langLabel: "语言",
   admin: "后台",
@@ -175,6 +177,8 @@ const enDict: Dict = {
   downloading: "Downloading…",
   downloadOk: "Download complete",
   downloadFail: "Download failed, please retry",
+  showMore: "Show all",
+  showLess: "Show less",
   share: "Share",
   langLabel: "Language",
   admin: "Admin",
@@ -291,6 +295,8 @@ const languageNames: Record<Lang, Dict> = {
   },
   ja: {
     brand: "ARK ライブラリー",
+    showMore: "すべて表示",
+    showLess: "閉じる",
     lang_zh_CN: "中国語",
     lang_en: "英語",
     lang_ja: "日本語",
@@ -301,6 +307,8 @@ const languageNames: Record<Lang, Dict> = {
   },
   ko: {
     brand: "ARK 라이브러리",
+    showMore: "모두 보기",
+    showLess: "접기",
     lang_zh_CN: "중국어",
     lang_en: "영어",
     lang_ja: "일본어",
@@ -311,6 +319,8 @@ const languageNames: Record<Lang, Dict> = {
   },
   vi: {
     brand: "Thư viện ARK",
+    showMore: "Xem tất cả",
+    showLess: "Thu gọn",
     lang_zh_CN: "Tiếng Trung",
     lang_en: "Tiếng Anh",
     lang_ja: "Tiếng Nhật",
@@ -321,6 +331,8 @@ const languageNames: Record<Lang, Dict> = {
   },
   id: {
     brand: "Perpustakaan ARK",
+    showMore: "Lihat semua",
+    showLess: "Tutup",
     lang_zh_CN: "Bahasa Tionghoa",
     lang_en: "Bahasa Inggris",
     lang_ja: "Bahasa Jepang",
@@ -331,6 +343,8 @@ const languageNames: Record<Lang, Dict> = {
   },
   ms: {
     brand: "Perpustakaan ARK",
+    showMore: "Lihat semua",
+    showLess: "Tutup",
     lang_zh_CN: "Bahasa Cina",
     lang_en: "Bahasa Inggeris",
     lang_ja: "Bahasa Jepun",