feat: complete i18n translation for remaining components

- Translate pages: Projects, ProjectHealthPage, ProjectSettings
- Translate components: TaskDetailModal, KanbanBoard, Comments,
  SubtaskList, CalendarView, BlockerDialog
- Add translation keys for tasks namespace: kanban, calendar,
  subtasks.error, comments.error, blockers (full translation)
- Add common.labels.task translation key
- Fix task creation: use original_estimate instead of time_estimate

Translation coverage:
- 10 locale files updated (zh-TW & en)
- 6 page/component files translated
- ~100 new translation keys added

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/public/locales/zh-TW/tasks.json

@@ -23,7 +23,8 @@
     "attachments": "附件",
     "comments": "留言",
     "watchers": "關注者",
-    "blockers": "阻擋項目"
+    "blockers": "阻擋項目",
+    "hours": "{{count}} 小時"
   },
   "status": {
     "todo": "待處理",
@@ -31,7 +32,11 @@
     "review": "審核中",
     "done": "已完成",
     "cancelled": "已取消",
-    "blocked": "被阻擋"
+    "blocked": "被阻擋",
+    "noStatus": "無狀態",
+    "unassigned": "未指派",
+    "noDueDate": "無截止日期",
+    "notEstimated": "未預估"
   },
   "priority": {
     "low": "低",
@@ -86,17 +91,32 @@
     "add": "新增子任務",
     "placeholder": "輸入子任務標題",
     "completed": "已完成 {{count}} / {{total}}",
-    "empty": "沒有子任務"
+    "count": "{{count}} 個子任務",
+    "empty": "沒有子任務",
+    "adding": "新增中...",
+    "error": {
+      "load": "載入子任務失敗",
+      "create": "建立子任務失敗"
+    }
   },
   "comments": {
     "title": "留言",
-    "add": "新增留言",
-    "placeholder": "輸入您的留言...",
+    "add": "發表留言",
+    "placeholder": "新增留言... 使用 @name 來提及某人",
     "edited": "已編輯",
     "delete": "刪除留言",
-    "confirmDelete": "確定要刪除此留言嗎？",
+    "confirmDelete": "確定要刪除此留言嗎？此操作無法復原。",
     "empty": "還沒有留言",
-    "reply": "回覆"
+    "reply": "回覆",
+    "mentioned": "提及",
+    "replyingTo": "回覆留言中",
+    "posting": "發送中...",
+    "error": {
+      "load": "載入留言失敗",
+      "post": "發表留言失敗",
+      "update": "更新留言失敗",
+      "delete": "刪除留言失敗"
+    }
   },
   "attachments": {
     "title": "附件",
@@ -113,7 +133,26 @@
     "blockedBy": "被以下任務阻擋",
     "blocking": "正在阻擋以下任務",
     "remove": "移除阻擋關係",
-    "empty": "沒有阻擋項目"
+    "empty": "沒有阻擋項目",
+    "taskBlocked": "任務被阻擋",
+    "markAsBlocked": "標記為阻擋",
+    "activeBlocker": "進行中的阻擋",
+    "reportedBy": "回報者",
+    "on": "於",
+    "resolutionNote": "解決說明",
+    "resolutionPlaceholder": "描述如何解決阻擋問題...",
+    "resolving": "解決中...",
+    "resolveBlocker": "解決阻擋",
+    "blockerReason": "阻擋原因",
+    "reasonPlaceholder": "描述阻擋此任務的原因...",
+    "history": "阻擋歷史",
+    "reported": "回報",
+    "resolved": "已解決",
+    "error": {
+      "load": "載入阻擋項目失敗",
+      "create": "建立阻擋項目失敗",
+      "resolve": "解決阻擋項目失敗"
+    }
   },
   "messages": {
     "created": "任務已建立",
@@ -126,6 +165,18 @@
     "attachmentUploaded": "附件已上傳",
     "confirmDelete": "確定要刪除此任務嗎？此操作無法復原。"
   },
+  "kanban": {
+    "dropHere": "將任務拖放至此"
+  },
+  "calendar": {
+    "allAssignees": "所有負責人",
+    "allPriorities": "所有優先順序",
+    "activeOnly": "僅進行中",
+    "completedOnly": "僅已完成",
+    "clearFilters": "清除篩選",
+    "overdue": "逾期",
+    "completed": "已完成"
+  },
   "empty": {
     "title": "沒有任務",
     "description": "目前沒有任務。建立您的第一個任務開始吧！",