按规划继续工作

结论：补齐 OPFS 会话快照自定义文件名与非法快照文件名拒绝验证，覆盖 Node OPFS 与 Chromium OPFS 路径，并通过 host/WASM/browser 聚合验证。

wasm-port/tests/opfs/node/verify_file_service.mjs

@@ -104,6 +104,10 @@ assert.equal(parameterFilePath("xyzab-tdr"), "linuxcnc/machines/xyzab-tdr/linuxc
 assert.equal(gcodeProgramPath("fixture.ngc"), "linuxcnc/gcode/fixture.ngc");
 assert.equal(previewCachePath("fixture"), "linuxcnc/preview-cache/fixture/preview.json");
 assert.equal(sessionSnapshotPath("session-1"), "linuxcnc/sessions/session-1/snapshot.json");
+assert.equal(
+  sessionSnapshotPath("session-1", "custom-snapshot.json"),
+  "linuxcnc/sessions/session-1/custom-snapshot.json",
+);
 assert.deepEqual(defaultMachinePaths("xyzab-tdr"), {
   ini: "linuxcnc/machines/xyzab-tdr/machine.ini",
   toolTable: "linuxcnc/machines/xyzab-tdr/tool.tbl",
@@ -167,6 +171,23 @@ await saveSessionSnapshot("session-1", snapshotPayload, {
   metadata: { source: "node-smoke" },
 });
 assert.deepEqual(await loadSessionSnapshot("session-1", { storage }), snapshot);
+const customSnapshot = await saveSessionSnapshot("session-1", snapshotPayload, {
+  storage,
+  filename: "custom-snapshot.json",
+  createdAt: "2026-06-08T00:00:00.000Z",
+  metadata: { source: "node-smoke-custom" },
+});
+assert.equal(
+  customSnapshot.metadata.source,
+  "node-smoke-custom",
+);
+assert.deepEqual(
+  await loadSessionSnapshot("session-1", {
+    storage,
+    filename: "custom-snapshot.json",
+  }),
+  customSnapshot,
+);
 
 await saveMachineTextFiles("xyzab-tdr", {
   ini: "[EMC]\nMACHINE = xyzab-tdr\n",
@@ -569,6 +590,24 @@ assert.throws(
   () => machineIniPath("../escape"),
   /Invalid machine id/,
 );
+assert.throws(
+  () => sessionSnapshotPath("session-1", "nested/snapshot.json"),
+  /Invalid session snapshot filename/,
+);
+await assert.rejects(
+  () => saveSessionSnapshot("session-1", {}, {
+    storage,
+    filename: "nested/snapshot.json",
+  }),
+  /Invalid session snapshot filename/,
+);
+await assert.rejects(
+  () => loadSessionSnapshot("session-1", {
+    storage,
+    filename: "../snapshot.json",
+  }),
+  /Invalid session snapshot filename/,
+);
 await assert.rejects(
   () => saveMachineTextFiles("xyzab-tdr", null, { storage }),
   /machine files must be a plain object/,