Adds "Viewed" tags to visited posts on pawchive.pw, with mark-as-unread support and artist-grouped history.浏览增强：自动标记已读帖子，按创作者分组查看浏览历史。
Better Pawchive enhances your browsing experience on pawchive.pw by automatically tracking which posts you've already visited.
Once a post is viewed, a green "viewed" tag appears on its card across artist pages, post listings, and the homepage — so you never waste time opening the same post twice.
Features:
- Automatically marks posts as "Viewed" when you visit them
- "Mark as Unread" button on every tagged post card
- Sidebar stats showing total tracked creators and posts
- View History overlay grouped by artist, with expand/collapse, individual deletion, per-artist clearing, and full history wipe
- Works seamlessly with the site's HTMX navigation — tags and stats stay up to date as you browse
Inspired by SirSalamandra/better-coomer-kemono, a browser extension for Coomer/Kemono.
提升 pawchive.pw 的浏览体验，自动标记已访问过的帖子。
浏览帖子后，帖子卡片上会出现绿色 "viewed" 标签，覆盖艺术家页、帖子列表和首页，不会重复点开同一个帖子。
功能：
- 浏览帖子后自动标记为"已读"
- 每个已标记的帖子卡片上都有"标为未读"按钮
- 侧边栏显示已追踪的创作者和帖子数量
- 按创作者分组的浏览历史面板，支持展开/折叠、单条删除、按创作者清除、全部清空
- 适配站点的 HTMX 动态导航，标签和统计随页面切换自动刷新
灵感来源于 SirSalamandra/better-coomer-kemono（Coomer/Kemono 的浏览器扩展）。
