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/browser/ini_panel_smoke.html

@@ -116,6 +116,43 @@ JOINTS = 3
       assertEqual(loadedSnapshot.createdAt, savedSnapshot.createdAt, "snapshot timestamp");
       assertEqual(loadedSnapshot.payload.files.ini, opfsPath, "snapshot payload");
       assertEqual(loadedSnapshot.metadata.source, "browser-smoke", "snapshot metadata");
+      assertEqual(
+        sessionSnapshotPath("browser-session", "browser-custom-snapshot.json"),
+        "linuxcnc/sessions/browser-session/browser-custom-snapshot.json",
+        "snapshot custom path",
+      );
+      const customSnapshot = await saveSessionSnapshot(
+        "browser-session",
+        snapshotPayload,
+        {
+          filename: "browser-custom-snapshot.json",
+          createdAt: "2026-06-08T00:00:00.000Z",
+          metadata: { source: "browser-smoke-custom" },
+        },
+      );
+      const loadedCustomSnapshot = await loadSessionSnapshot(
+        "browser-session",
+        { filename: "browser-custom-snapshot.json" },
+      );
+      assertEqual(
+        loadedCustomSnapshot.metadata.source,
+        customSnapshot.metadata.source,
+        "custom snapshot metadata",
+      );
+      await assertRejects(
+        "browser snapshot invalid filename save",
+        () => saveSessionSnapshot("browser-session", {}, {
+          filename: "nested/snapshot.json",
+        }),
+        /Invalid session snapshot filename/,
+      );
+      await assertRejects(
+        "browser snapshot invalid filename load",
+        () => loadSessionSnapshot("browser-session", {
+          filename: "../snapshot.json",
+        }),
+        /Invalid session snapshot filename/,
+      );
       await saveTextFile(
         sessionSnapshotPath("browser-bad-format"),
         JSON.stringify({