feat(i18n): 外观页 40 条文案进词表（M180 I18NAPPEAR）

- 卡片内 22 处硬编码英文（整窗/面板透明度、背景图开关+路径、填充、暗化、配色来源）全部改走 Key
- 运行时诊断改成 key + 参数：`background::Note`（读盘/解码/过大/小图平铺）、`state::backend_note`、
  `palette::note` 全部返回 Key；`state.rs` 只留 key、不放文案表（390 → 391 行）
- 上限/下限常量走占位符 `{floor}` / `{max}` / `{limit}` / `{requested}`；`{:.2}` 在 Rust 侧格式化好
  再套模板（`Catalog::render` 只认 `{name}`）
- 新增 40 条 key（中英各一条），按装配链锚点插在 `SettingsAppearanceCornerSuspended` 之后，
  金表 `golden/tail.rs` 同位置插入 40 行（`rows() == len() == Key::ALL.len()`）
- 守卫三条：中文渲染全非 ASCII、卡片 key 全覆盖（改回写死英文即红）、外观 key 逐条真翻过
- probe 加第二条取证路（`record_rendered`），`take()` 签名不动（M179 的守卫在 scope 外）

crates/i18n/src/catalog/golden/tail.rs

@@ -29,6 +29,50 @@ pub(super) const ROWS: &[(&str, &str, &str)] = &[
     ("SettingsAppearanceCornerSquare", "Square", "直角"),
     ("SettingsAppearanceCornerHint", "On Windows 11 and Server 2025 we ask the system for rounded corners; Windows 10 keeps square corners. On macOS and Linux the desktop's own rules apply. We never draw corners ourselves.", "Windows 11 与 Windows Server 2025 上我们请求系统处理外框圆角；Windows 10 保持直角；macOS 与 Linux 交给桌面合成器自己的规则；我们不自己画圆角。"),
     ("SettingsAppearanceCornerSuspended", "Not in effect right now: window transparency is below 100%. Setting it back to 100% restores the rounded corners.", "当前因整窗透明度不生效：把整窗透明度调回 100% 圆角即恢复。"),
+    // M180：外观分组补齐（`catalog/settings/appearance.rs` 的第二批，M116 圆角那 5 条之后）。
+    // 位置就是装配链里那个域的位置——`settings_appearance_entries` 在 `settings_java_entries` 之前，
+    // 所以这 40 行必须落在 `SettingsAppearanceCornerSuspended` 与 `SettingsJavaScan` 之间
+    // （顺序 = `Key::ALL`；为排到文件尾而重排别人的族会让 `split_keeps_every_translation` 整片红）。
+    ("SettingsAppearanceWindowOpacity", "Window transparency", "整窗透明度"),
+    ("SettingsAppearanceWindowOpacityHint", "Applies to the whole window. Floor {floor}; 1.00 = fully opaque.", "作用于整个窗口。下限 {floor}；1.00 = 完全不透明。"),
+    ("SettingsAppearancePanelOpacity", "Panel transparency", "面板透明度"),
+    ("SettingsAppearancePanelOpacityHint", "Only the panel/card layer. Floor {floor}; independent of window transparency.", "只作用于面板 / 卡片这一层。下限 {floor}；与整窗透明度互不影响。"),
+    ("SettingsAppearancePanelOpacityForcedValue", "100% (forced from {requested})", "100%（强制，原请求值 {requested}）"),
+    ("SettingsAppearancePanelOpacityForcedHint", "Software renderer: panels stay fully opaque (window transparency still works).", "软件渲染：面板恒为不透明（整窗透明度仍然有效）。"),
+    ("SettingsAppearanceBackgroundImage", "Background image", "背景图"),
+    ("SettingsAppearanceOff", "Off", "关"),
+    ("SettingsAppearanceOn", "On", "开"),
+    ("SettingsAppearanceImagePath", "Image path", "图片路径"),
+    ("SettingsAppearancePaletteLevel", "Colours: {level}", "配色：{level}"),
+    ("SettingsAppearanceBgFill", "Fill", "填充方式"),
+    ("SettingsAppearanceBgFillCover", "Cover", "铺满"),
+    ("SettingsAppearanceBgFillContain", "Contain", "完整显示"),
+    ("SettingsAppearanceBgFillTile", "Tile", "平铺"),
+    ("SettingsAppearanceBgDim", "Dim", "暗化"),
+    ("SettingsAppearanceBgDimHint", "Blends the image toward the panel colour so text stays readable. Max {max}.", "把背景图往面板底色上退，让文字读得清。上限 {max}。"),
+    ("SettingsAppearancePaletteSource", "Colour source", "配色来源"),
+    ("SettingsAppearancePaletteBackground", "Background", "取自背景图"),
+    ("SettingsAppearancePaletteWallpaper", "Wallpaper", "取自壁纸"),
+    ("SettingsAppearancePalettePreset", "Preset", "内置色卡"),
+    ("SettingsAppearanceSoftwareRendererNote", "Software renderer: panel transparency and glass stay fully opaque (window transparency still works).", "软件渲染：面板透明度与玻璃效果恒为不透明（整窗透明度仍然有效）。"),
+    ("SettingsAppearanceBgReadFailed", "Background image could not be read: {reason}", "背景图读不出来：{reason}"),
+    ("SettingsAppearanceBgDecodeFailed", "Background image could not be decoded ({reason}; this build decodes PNG, JPEG and BMP)", "背景图解不开（{reason}；这个构建只支持 PNG、JPEG 与 BMP）"),
+    ("SettingsAppearanceBgTooLarge", "Background image is too large to decode: {width}×{height} (limit {limit} px per edge)", "背景图太大，解不开：{width}×{height}（每边上限 {limit} 像素）"),
+    ("SettingsAppearanceBgSmallTile", "Small image ({width}×{height}): tiles are scaled up so the window stays covered (max {max} tiles, no gaps).", "图片很小（{width}×{height}）：图块会被放大，保证窗口铺满（最多 {max} 块，不留缝）。"),
+    ("SettingsAppearancePaletteBgUndecodable", "Background image could not be read; colours fall back.", "背景图读不出来，配色回落到下一级。"),
+    ("SettingsAppearancePaletteBgTooSmall", "Background image is too small to sample; colours fall back.", "背景图太小，取不了色，配色回落到下一级。"),
+    ("SettingsAppearancePaletteBgBadDimensions", "Background image data looks inconsistent; colours fall back.", "背景图数据前后不一致，配色回落到下一级。"),
+    ("SettingsAppearancePaletteBgNoOpaquePixels", "Background image is almost fully transparent; colours fall back.", "背景图几乎全透明，配色回落到下一级。"),
+    ("SettingsAppearancePaletteBgLowChroma", "Background image is too monochrome to tint from; colours fall back.", "背景图太单调（彩度不足），取不出配色，回落到下一级。"),
+    ("SettingsAppearancePaletteBgContrast", "Background image colours would be unreadable; colours fall back.", "按背景图取的颜色读不清，配色回落到下一级。"),
+    ("SettingsAppearancePaletteWallpaperUndecodable", "Desktop wallpaper could not be read.", "桌面壁纸读不出来。"),
+    ("SettingsAppearancePaletteWallpaperTooSmall", "Desktop wallpaper is too small to sample.", "桌面壁纸太小，取不了色。"),
+    ("SettingsAppearancePaletteWallpaperBadDimensions", "Desktop wallpaper data looks inconsistent.", "桌面壁纸数据前后不一致。"),
+    ("SettingsAppearancePaletteWallpaperNoOpaquePixels", "Desktop wallpaper is almost fully transparent.", "桌面壁纸几乎全透明。"),
+    ("SettingsAppearancePaletteWallpaperLowChroma", "Desktop wallpaper is too monochrome to tint from.", "桌面壁纸太单调（彩度不足），取不出配色。"),
+    ("SettingsAppearancePaletteWallpaperContrast", "Desktop wallpaper colours would be unreadable; colours fall back.", "按桌面壁纸取的颜色读不清，配色回落到下一级。"),
+    ("SettingsAppearancePalettePresetContrast", "The built-in card needed a small contrast correction.", "内置色卡做了一点对比度修正。"),
+    ("SettingsAppearancePaletteAdjusted", "A few colours were nudged for readability.", "有几个颜色为了可读性做了微调。"),
     // M175：设置页「Java」分组（`catalog/settings/java.rs` 的 `settings_java_entries`）。
     // 位置就是装配链里那个域的位置：`settings_java_entries` 在 `settings_appearance_entries` 之后、
     // `settings_download_entries`（空）与 `settings_ai_entries`（M174）之前，所以这几行必须落在