refactor: clean up unused code and simplify imports

- Remove unused imports and variables across 35 files
- Simplify component logic and remove dead code
- Clean up test files by removing unnecessary setup
- Streamline CI workflow configuration

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/pages/Timestamp/LiveClock.tsx

@@ -4,7 +4,7 @@ import CopyButton from '@/components/CopyButton';
 import { useSnackbar } from '@/components/GlobalSnackbar';
 import type { UnitType } from './constants';
 import { useI18n } from '@/utils/chromeI18n';
-import { cn } from '@/lib/utils'; // 引入标准的 shadcn 工具函数
+import { cn } from '@/lib/utils';
 
 interface LiveClockProps extends React.HTMLAttributes<HTMLDivElement> {
   unit: UnitType;
@@ -24,12 +24,10 @@ const LiveClock = React.memo(({ unit, onUseNow, className, ...props }: LiveClock
     };
   });
 
-  // 始终保持外部回调指针最新
   useEffect(() => {
     onUseNowRef.current = onUseNow;
   }, [onUseNow]);
 
-  // 2. 高频高灵敏度计时器 (200ms 刷新率)
   useEffect(() => {
     const tick = () => {
       const rightNow = Date.now();

src/pages/Timestamp/ResultView.tsx

@@ -4,14 +4,14 @@ import CopyButton from '@/components/CopyButton';
 import type { UnitType } from './constants';
 import { DATE_FORMAT } from './constants';
 import { useI18n } from '@/utils/chromeI18n';
-import { cn } from '@/lib/utils'; // shadcn 核心类名合并工具
+import { cn } from '@/lib/utils';
 
 interface ResultViewProps extends React.HTMLAttributes<HTMLDivElement> {
   result: string;
   mode: 'ts2dt' | 'dt2ts';
   unit: UnitType;
   zone: string;
-  /** 无结果时是否渲染占位（桌面端右栏使用），默认 false */
+
   showEmptyPlaceholder?: boolean;
 }
 
@@ -27,7 +27,6 @@ const ResultView = React.memo(
   }: ResultViewProps) => {
     const { t } = useI18n('timestamp');
 
-    // 严谨计算时间衍生的附加时区/相对时间状态
     const extraInfo = useMemo(() => {
       if (!result) return null;
       const d =
@@ -44,7 +43,6 @@ const ResultView = React.memo(
       };
     }, [result, mode, zone, unit]);
 
-    // 1. 空状态骨架面板：优雅匹配 shadcn 的中性灰色居中占位
     if (!result) {
       if (!showEmptyPlaceholder) return null;
       return (
@@ -95,7 +93,7 @@ const ResultView = React.memo(
                 <span
                   className={cn(
                     'text-xs text-foreground/90 font-medium break-all text-left sm:text-right tabular-nums',
-                    item.isMono && 'font-mono text-[11px]', // ISO/UTC 等机器时间使用精细化等宽代码体
+                    item.isMono && 'font-mono text-[11px]',
                   )}
                 >
                   {item.value}

src/pages/Timestamp/index.tsx

@@ -76,7 +76,7 @@ export default function Index() {
                   ]}
                   onChange={(v) => setUnit(v as 'ms' | 's')}
                   size="small"
-                  className="sm:w-auto shrink-0" // 窄屏下全宽，宽屏下自适应收缩
+                  className="sm:w-auto shrink-0"
                 />
 
                 <Select value={zone} onValueChange={(v: string) => setZone(v as typeof zone)}>

src/pages/Timestamp/useTimestampConverter.ts

@@ -7,7 +7,7 @@ import { useContextMenuData } from '@/utils/useContextMenuData';
 
 export interface UseTimestampConverterReturn {
   mode: 'ts2dt' | 'dt2ts';
-  input: string; // 统一为单一受控输入源
+  input: string;
   unit: UnitType;
   zone: ZoneType;
   result: string;