feat(upload): resumable chunked upload protocol for large files — init(parts≤32MB)/status/complete endpoints with fingerprint-derived deterministic uploadId (same file resumes, no restart), sessions in BOOKS_DIR/.uploads with 24h sweep, frontend uploadBook auto-switches >16MB to 8MB parts (retry x3 in place, skip received); oversize single POST now reports honest 413 too_large instead of "multipart field 'file' required" (was MaxBytesReader abort mislabeled); UPLOAD_MAX_MB wired into both compose stacks (cap total, .env.example 2048), nginx body limit drops to 32m; testCfg limit 1MB, CJK/fullwidth-colon filename proven unaffected; e2e verified with 311MB real file (39 parts, sha1 match)

frontend/src/api/client.ts

@@ -113,6 +113,33 @@ export function formatPageUrl(fmt: string, n: number): string {
   return fmt.replace("%d", String(n));
 }
 
+const SINGLE_MAX = 16 << 20;
+const CHUNK_SIZE = 8 << 20;
+const PART_RETRY = 3;
+
+async function uploadChunked(id: number, file: File): Promise<{ accepted: boolean; path: string }> {
+  const { uploadId } = await apiFetch<{ uploadId: string }>(`/libraries/${id}/upload/init`, {
+    method: "POST",
+    body: { name: file.name, size: file.size, chunkSize: CHUNK_SIZE },
+  });
+  const { received } = await apiFetch<{ received: number[] }>(`/uploads/${uploadId}`);
+  const have = new Set(received);
+  const n = Math.ceil(file.size / CHUNK_SIZE);
+  for (let i = 0; i < n; i++) {
+    if (have.has(i)) continue;
+    for (let tries = 0; ; tries++) {
+      const res = await fetch(full(`/uploads/${uploadId}/parts/${i}`), {
+        method: "PUT",
+        headers: { ...authHeaders(), "Content-Type": "application/octet-stream" },
+        body: file.slice(i * CHUNK_SIZE, Math.min((i + 1) * CHUNK_SIZE, file.size)),
+      });
+      if (res.ok) break;
+      if (tries >= PART_RETRY) throw await toHttpError(res);
+    }
+  }
+  return apiFetch<{ accepted: boolean; path: string }>(`/uploads/${uploadId}/complete`, { method: "POST" });
+}
+
 export const api = {
   login: (username: string, password: string) =>
     apiFetch<{ token: string }>("/auth/login", { method: "POST", body: { username, password } }),
@@ -126,14 +153,15 @@ export const api = {
   listLibraries: () => apiFetch<Library[]>("/libraries"),
   createLibrary: (name: string) => apiFetch<Library>("/libraries", { method: "POST", body: { name } }),
   scanLibrary: (id: number) => apiFetch<{ accepted: boolean }>(`/libraries/${id}/scan`, { method: "POST" }),
-  uploadBook: (id: number, file: File) => {
-    const fd = new FormData();
-    fd.append("file", file);
-    return apiFetch<{ accepted: boolean; path: string }>(`/libraries/${id}/upload`, {
-      method: "POST",
-      form: fd,
-    });
-  },
+  // ≤16MB 单 POST;更大走分片协议(init→parts→complete),失败分片原地重试,已传分片跳过
+  uploadBook: (id: number, file: File): Promise<{ accepted: boolean; path: string }> =>
+    file.size <= SINGLE_MAX
+      ? (() => {
+          const fd = new FormData();
+          fd.append("file", file);
+          return apiFetch<{ accepted: boolean; path: string }>(`/libraries/${id}/upload`, { method: "POST", form: fd });
+        })()
+      : uploadChunked(id, file),
 
   listBooks: (params: { library?: number; q?: string } = {}) => {
     const sp = new URLSearchParams();