feat(lib): shelf sort/section pure helpers + formatSize extraction, table tests

frontend/test/shelf.test.ts

@@ -0,0 +1,25 @@
+import { expect, it } from "vitest";
+import type { Book } from "../src/api/types";
+import { sections, sortBooks } from "../src/lib/shelf";
+
+const b = (over: Partial<Book>): Book =>
+  ({ id: 1, path: "p", title: "t", format: "cbz", size: 1, pages: 1, percent: 0, added_at: "2026-01-01T00:00:00Z", library_id: 1, state: "ready", cover_url: "", page_url_fmt: "", pages_url: "", error: "", ...over }) as Book;
+
+it("sortBooks: added 新→旧 / title zh 本地化 / progress 高→低且并列按 added", () => {
+  const old = b({ id: 1, added_at: "2026-01-01T00:00:00Z", title: "b" });
+  const nw = b({ id: 2, added_at: "2026-02-01T00:00:00Z", title: "a" });
+  expect(sortBooks([old, nw], "added").map((x) => x.id)).toEqual([2, 1]);
+  expect(sortBooks([old, nw], "title").map((x) => x.id)).toEqual([2, 1]);
+  expect(sortBooks([b({ id: 3, percent: 0.2 }), b({ id: 4, percent: 0.9 })], "progress").map((x) => x.id)).toEqual([4, 3]);
+  const tie = [b({ id: 5, percent: 0.5, added_at: "2026-01-01T00:00:00Z" }), b({ id: 6, percent: 0.5, added_at: "2026-03-01T00:00:00Z" })];
+  expect(sortBooks(tie, "progress").map((x) => x.id)).toEqual([6, 5]);
+});
+
+it("sections: flat 单段无标题;dir 按目录分组且组内排序、根目录置顶", () => {
+  const books = [b({ id: 1, path: "x/a.cbz" }), b({ id: 2, path: "b.cbz", title: "B" }), b({ id: 3, path: "x/c.cbz", title: "A" })];
+  // 容器 Intl zh 实测序 A < B < t (localeCompare("zh")),故 title 升序为 id3,id2,id1
+  expect(sections(books, "title", "flat")).toEqual([{ label: "", books: [books[2], books[1], books[0]] }]);
+  const g = sections(books, "title", "dir");
+  expect(g.map((s) => s.label)).toEqual(["", "x"]);
+  expect(g[1].books.map((x) => x.title)).toEqual(["A", "t"]); // x 组内按 title 排序
+});