[optimization] Added Wan 2.2 VAE decode optimizations (#7056)

Signed-off-by: Maciej Bala <mbala@nvidia.com>
Signed-off-by: MaciejBalaNV <mbala@nvidia.com>

tests/entrypoints/test_serve.py

@@ -81,6 +81,23 @@ def test_serve_parser_accepts_no_async_chunk_and_marks_it_explicit() -> None:
     assert "api_server_count" not in explicit
 
 
+def test_serve_parser_accepts_vae_fast_path() -> None:
+    parser = TrackingArgumentParser()
+    subparsers = parser.add_subparsers(dest="subcommand")
+    OmniServeCommand().subparser_init(subparsers)
+
+    args = parser.parse_args(["serve", "fake-model", "--omni"])
+    assert args.vae_fast_path == "lossless"
+    assert "vae_fast_path" not in args.get_explicit_kwargs_dict()
+
+    args = parser.parse_args(["serve", "fake-model", "--omni", "--vae-fast-path", "channels_last"])
+    assert args.vae_fast_path == "channels_last"
+    assert args.get_explicit_kwargs_dict()["vae_fast_path"] == "channels_last"
+
+    with pytest.raises(SystemExit):
+        parser.parse_args(["serve", "fake-model", "--omni", "--vae-fast-path", "fast"])
+
+
 def _parse_serve_args(argv: list[str]) -> TrackingNamespace:
     """Parse a ``serve`` argv through the real Omni parser, returning the
     TrackingNamespace (with ``explicit_keys``) that ``validate`` receives."""