feat: review and dismiss duplicate books

Adds the per-library review screen, a muted note in the upload tray for a book
that may already be held, and the remote functions behind them. The tray note
is deliberately weaker than the file-level one, which means something stronger.

frontend/src/lib/api/book.remote.ts

@@ -8,8 +8,10 @@ import {
 	deleteBooksSchema,
 	editBookMetadataSchema,
 	updateBookProgressSchema,
+	duplicateDismissalSchema,
 	type Book,
 	type BooksUploadResult,
+	type DuplicateBookGroup,
 	bookFilesUpload
 } from '$lib/schema/index';
 import { stringCoerce, type PaginatedResponse } from '$lib/schema/common';
@@ -153,6 +155,47 @@ export const deleteBookFiles = command(deleteBookFilesSchema, async ({ book_id,
 	}
 });
 
+/**
+ * Books already in the library that look like copies of one another.
+ *
+ * Metadata only, so every group is a question rather than a verdict — which is why
+ * the screen it feeds offers a way to disagree.
+ */
+export const listDuplicateBooks = query(
+	stringCoerce,
+	async (libraryId): Promise<DuplicateBookGroup[]> => {
+		const { locals } = getRequestEvent();
+
+		const response = await locals.api.get(`/books/duplicate-books?library_id=${libraryId}`);
+
+		if (!response.ok) error(response.status, detailOf(await response.text()));
+
+		return await response.json();
+	}
+);
+
+/** Record that two books are not the same book, so the pair stops being proposed. */
+export const dismissDuplicateBooks = command(duplicateDismissalSchema, async (data) => {
+	const { locals } = getRequestEvent();
+
+	const response = await locals.api.post('/books/duplicate-books/dismissals', data);
+
+	if (!response.ok) error(response.status, detailOf(await response.text()));
+});
+
+/** Undo a dismissal, so the pair is proposed again. */
+export const restoreDuplicateBooks = command(duplicateDismissalSchema, async (data) => {
+	const { locals } = getRequestEvent();
+
+	const params = createQueryParams(data);
+
+	const response = await locals.api.delete(
+		`/books/duplicate-books/dismissals?${params.toString()}`
+	);
+
+	if (!response.ok) error(response.status, detailOf(await response.text()));
+});
+
 export const updateBookProgress = command(
 	updateBookProgressSchema,
 	async ({ book_ids, ...data }) => {