feat(libs): create library by name only; root_path derived server-side as BOOKS_DIR/SafeName(name), validated at creation; drop root_path input from admin UI; align changelogs to bilingual template; trim AGENTS.md to rules not derivable from repo layout

docs/CHANGELOG.md

@@ -1,10 +1,16 @@
-# Changelog
+# Changelog / 更新日志
 
-All non-WebUI user-visible changes. Newest version on top.
+All notable non-WebUI user-visible changes should be documented in this file, newest version on top.
+本文件记录所有非 WebUI 的重要用户可见变更，最新版本在最上方。
+
+The format loosely follows Keep a Changelog and can be adapted to the team's habits.
+本文档参考了 Keep a Changelog 的思路，也可以根据团队习惯调整。
 
 ## [Unreleased]
 
-### Changed
+### Changed / 变更
 
+- API: `POST /api/libraries` now takes only `{name}`; `root_path` is generated server-side as `BOOKS_DIR/<sanitized name>` (no client-supplied paths, validated at creation).
+- API：`POST /api/libraries` 只需 `{name}`；`root_path` 由服务端生成为 `BOOKS_DIR/<清洗后的库名>`（不再接受客户端指定路径，创建时即校验）。
 - Repo structure conformed to `AGENTS.md`: `web/` renamed to `frontend/`; backend HTTP layer moved from `internal/api` to `cmd/webui/{api,handlers}` (`cmd/server` → `cmd/webui`); README/CHANGELOGs relocated under `docs/` (`README_zh.md` added as Chinese mirror); module-level `.gitignore`s added (`backend/`, `deploy/`); stray root `library/` removed (book files live in `deploy/api/storage/`); debug binaries untracked.
 - Docs: `docs/README.md` is now the English primary; previous Chinese README mirrored to `docs/README_zh.md`.

docs/CHANGELOG_web.md

@@ -1,7 +1,16 @@
-# Changelog (WebUI)
+# Changelog (WebUI) / 更新日志
 
-All WebUI user-visible changes. Newest version on top.
+All notable WebUI user-visible changes should be documented in this file, newest version on top.
+本文件记录所有 WebUI 的重要用户可见变更，最新版本在最上方。
+
+The format loosely follows Keep a Changelog and can be adapted to the team's habits.
+本文档参考了 Keep a Changelog 的思路，也可以根据团队习惯调整。
 
 ## [Unreleased]
 
+### Changed / 变更
+
+- Creating a library on the admin Libraries page no longer asks for a server-side absolute path; just a name (the directory lands at `BOOKS_DIR/<name>` automatically).
+- 库管理页建库不再要求填写服务端绝对路径，只需库名（目录自动落在 `BOOKS_DIR/<库名>` 下）。
+
 _No WebUI user-visible changes in this release; the structural refactor (`web/` → `frontend/`) does not affect the served app._

docs/superpowers/specs/2026-09-04-book-comic-library-design.md

@@ -77,7 +77,7 @@ POST   /api/users                               ★ {username,password,role}
 DELETE /api/users/{id}                          ★
 
 GET    /api/libraries
-POST   /api/libraries                           ★ {name,root_path}
+POST   /api/libraries                           ★ {name} → root_path 由服务端生成(BooksDir/清洗后的库名)
 POST   /api/libraries/{id}/scan                 ★ → 202 异步
 POST   /api/libraries/{id}/upload  multipart    ★ → 202