fix(adapters): crossDeviceMove verifies pre-existing target with sha256 before deleting source

With the default hash="size", a target that already existed with the same
size but different content was treated as "already copied" and the source
was deleted (data loss; REQ §2.1 cleanup needs verified import). The
pre-existing-target comparison now always uses sha256; test covers the
same-size/different-content case with default options.

Co-Authored-By: Claude Fable 5.1 <[email protected]>

packages/adapters/src/fs/fs.test.ts

@@ -121,6 +121,10 @@ describe("moveSafe / crossDeviceMove", () => {
     expect(await readFile(t.path("src/b.mkv"), "utf8")).toBe("bbbb");
     const r4 = await crossDeviceMove(t.path("src/none.mkv"), t.path("dst/b.mkv"));
     expect(r4.status).toBe("attention");
+    // 默认 hash=size 时,已存在的同尺寸异内容目标也必须判为不一致,不得删源
+    const r5 = await crossDeviceMove(t.path("src/b.mkv"), t.path("dst/b.mkv"));
+    expect(r5.status).toBe("failed");
+    expect(await readFile(t.path("src/b.mkv"), "utf8")).toBe("bbbb");
   });
 
   it.skipIf(isRoot)("删源失败 → attention(以 root 运行时跳过:root 无视目录权限)", async () => {

packages/adapters/src/fs/move.ts

@@ -97,7 +97,7 @@ async function exists(p: string): Promise<boolean> {
 
 /**
  * 跨设备搬运:copy → verify → delete_source,每步返回日志,可重入:
- * - 目标已存在且与源一致 → copy 记为 skipped(上次已完成);不一致 → failed,不覆盖
+ * - 目标已存在且与源一致(强制 sha256)→ copy 记为 skipped(上次已完成);不一致 → failed,不覆盖
  * - 源已不存在但目标在,且上次日志 verify=done → 视为删源已完成
  * - 删源失败 → attention(不能报成功)
  */
@@ -138,7 +138,8 @@ export async function crossDeviceMove(src: string, dst: string, opts: CrossMoveO
 
   if (dstExists) {
     try {
-      if (await filesMatch(src, dst, method)) log("copy", "skipped", "target already matches source");
+      // 目标不是本次写出的:只比大小/抽样会把同尺寸的不同文件当成一致并删源,这里一律用 sha256
+      if (await filesMatch(src, dst, "sha256")) log("copy", "skipped", "target already matches source");
       else {
         log("copy", "failed", "target exists and differs", new FsError("EEXIST", `target exists: ${dst}`));
         return { status: "failed", steps };