style: 移除 emoji, 注释改为中文 (保留专业名词)

- 移除所有 Vue 组件和 README 中的 emoji (按钮文字、标题、功能列表)
- 将 src 下所有英文注释改为中文, 保留专业名词 (RRULE, EXDATE, ICS 等)
- 涉及文件: date.js, event-factory.js, ical-io.js, organize.js,
  recur.js, split.js, weekday.js, useCalendar.js, EventDetail.vue,
  App.vue, DropZone.vue, EventList.vue, HeaderBar.vue, README.md

src/components/DropZone.vue

@@ -39,7 +39,7 @@ function onPick(e) {
     @drop.prevent="onDrop"
   >
     <div class="dropzone-content">
-      <div class="icon">📅</div>
+      <div class="icon">日历</div>
       <p class="hint">拖入 .ics 文件，或</p>
       <label class="pick-btn">
         点击选择文件

src/components/EventDetail.vue

@@ -7,7 +7,7 @@ import OccurrenceGrid from './OccurrenceGrid.vue'
 
 const { selectedEvent, updateEvent, deleteEvent, splitEvent, toggleOccurrence } = useCalendar()
 
-// Local form state, synced when selection changes
+// 本地表单状态, 选择切换时同步
 const form = ref({})
 const showSplit = ref(false)
 const splitDate = ref('')
@@ -94,7 +94,7 @@ function onToggleOcc(date) {
 <template>
   <div v-if="!selectedEvent" class="empty">从左侧选择一个日程进行编辑</div>
   <div v-else class="detail">
-    <!-- Basic info -->
+    <!-- 基本信息 -->
     <div class="section-title">基本信息</div>
     <div class="form-group">
       <label>标题 (SUMMARY)</label>
@@ -119,7 +119,7 @@ function onToggleOcc(date) {
       <textarea v-model="form.description"></textarea>
     </div>
 
-    <!-- RRULE -->
+    <!-- 重复规则 (RRULE) -->
     <div class="section-title">重复规则 (RRULE)</div>
     <div class="form-group">
       <label>
@@ -156,7 +156,7 @@ function onToggleOcc(date) {
       </div>
     </div>
 
-    <!-- Occurrence grid -->
+    <!-- occurrence / 排除日期网格 -->
     <div v-if="form.is_recurring" class="section-title">occurrence / 排除日期</div>
     <OccurrenceGrid
       v-if="form.is_recurring && selectedEvent.rrule"
@@ -164,7 +164,7 @@ function onToggleOcc(date) {
       @toggle="onToggleOcc"
     />
 
-    <!-- Toolbar -->
+    <!-- 工具栏 -->
     <div class="toolbar">
       <button class="btn btn-primary" @click="applyChanges">应用更改</button>
       <button
@@ -172,12 +172,12 @@ function onToggleOcc(date) {
         class="btn btn-secondary"
         @click="showSplit = !showSplit"
       >
-        ✂ 拆分此日程
+        拆分此日程
       </button>
       <button class="btn btn-danger" @click="onDelete">删除此日程</button>
     </div>
 
-    <!-- Split panel -->
+    <!-- 拆分面板 -->
     <div v-if="showSplit && selectedEvent.rrule" class="split-panel">
       <p>从指定日期起，把此重复事件拆成前后两段。</p>
       <input type="date" v-model="splitDate" />

src/components/EventList.vue

@@ -15,7 +15,7 @@ function dowFor(ev) {
     <div class="stat">
       共 {{ stats.total }} 个日程（{{ stats.recurring }} 重复 / {{ stats.single }} 单次）
     </div>
-    <button class="add-btn" @click="addEvent">➕ 新增日程</button>
+    <button class="add-btn" @click="addEvent">新增日程</button>
     <div class="list">
       <div
         v-for="ev in state.events"

src/components/HeaderBar.vue

@@ -41,13 +41,13 @@ function onDownload() {
 <template>
   <div class="header-actions">
     <button class="btn btn-primary" @click="onOrganize" :disabled="state.events.length === 0">
-      🔁 整理去重
+      整理去重
     </button>
-    <button class="btn btn-secondary" @click="undo" :disabled="!canUndo">↶ 撤销</button>
-    <button class="btn btn-secondary" @click="redo" :disabled="!canRedo">↷ 重做</button>
-    <button class="btn btn-secondary" @click="onImport">📥 导入文件</button>
+    <button class="btn btn-secondary" @click="undo" :disabled="!canUndo">撤销</button>
+    <button class="btn btn-secondary" @click="redo" :disabled="!canRedo">重做</button>
+    <button class="btn btn-secondary" @click="onImport">导入文件</button>
     <button class="btn btn-success" @click="onDownload" :disabled="state.events.length === 0">
-      ⬇ 下载 ICS
+      下载 ICS
     </button>
     <span v-if="state.dirty" class="dirty-dot" title="有未保存更改">●</span>
     <input ref="fileInput" type="file" accept=".ics" @change="onFilePicked" hidden />