fix(deploy): pin distinct image tags per compose (booklib/{api,web}:{dev,prod}); same project name shared default tags so dev up without --build ran the prod image

frontend/test/group.test.ts

@@ -0,0 +1,20 @@
+import { expect, it } from "vitest";
+import { groupByDir } from "../src/lib/group";
+import type { Book } from "../src/api/types";
+
+let seq = 1;
+const mk = (path: string): Book => ({
+  id: seq++, library_id: 1, path, title: path, format: "cbz", size: 1, mtime: 1, pages: 0,
+  state: "ready", error: "", added_at: "", percent: 0, cover_url: "/api/books/0/cover",
+});
+
+it("根目录组为空串且排最前;目录组按字典序;组内保持输入顺序", () => {
+  const gs = groupByDir([mk("b.cbz"), mk("z/1.cbz"), mk("a/2.cbz"), mk("a/sub/3.cbz")]);
+  expect(gs.map((g) => g.dir)).toEqual(["", "a", "a/sub", "z"]);
+  expect(gs[0].books.map((x) => x.path)).toEqual(["b.cbz"]);
+  expect(gs[1].books.map((x) => x.path)).toEqual(["a/2.cbz"]);
+});
+
+it("空输入出空数组", () => {
+  expect(groupByDir([])).toEqual([]);
+});