refactor(settings): remove blocked addresses setting and block user/board feature

Obsolete with pseudonymity mode (user IDs randomized per board) and custom boards
requiring explicit search/subscribe. Unsubscribe suffices for boards.

public/translations/zh/default.json

@@ -138,15 +138,6 @@
   "posts_last_synced_info": "帖子最后同步于 {{time}}，此看板可能处于离线状态，发布可能会失败。",
   "newer_than": "新于",
   "no_threads": "没有帖子",
-  "unblock": "解除封禁",
-  "unblock_all": "解除全部封禁",
-  "blocked_addresses": "被阻止的地址",
-  "you_have_not_blocked": "您尚未封锁任何板块地址或用户地址。",
-  "block_user": "封锁用户",
-  "unblock_user": "解除封锁用户",
-  "block_board": "封锁论坛",
-  "unblock_board": "解除封锁论坛",
-  "unblock_all_confirm": "您确定要解锁所有论坛地址和用户地址吗？",
   "hidden": "隐藏",
   "save_options": "保存选项",
   "filters": "过滤器",
@@ -220,7 +211,6 @@
   "field_too_long": "字段太长。",
   "unsubscribe_all": "取消所有订阅",
   "unsubscribe_all_confirm": "您确定要取消对所有板块的订阅吗？",
-  "you_have_blocked_this_board": "您已屏蔽此板块",
   "looking_for_more_posts": "寻找更多帖子",
   "loading_feed": "加载中...",
   "loading_post": "正在加载帖子",