feat: ImageSequenceArtifact as input to NukeScriptNode

[hutchinson]

Background

PR #57 landed ImageSequenceArtifact support as an output from NukeScriptNode —
when a Nuke script renders a frame sequence, we collect the files and return them as a
ListArtifact[ImageUrlArtifact]. Kate's review comment surfaced the gap: feeding a
frame sequence into a Nuke script is equally common (e.g. upstream render → Nuke comp
→ downstream deliverable) and is currently unsupported.

Current State

• ImageSequenceArtifact appears in _OUTPUT_ARTIFACT_TYPES (Annotator panel) and is
  handled in _path_to_artifact() in nuke_script_node.py.
• It is absent from _INPUT_ARTIFACT_TYPES in the Annotator panel.
• input_types on dynamically created input parameters does not include
  ImageSequenceArtifact (or ListArtifact).
• _artifact_to_path() in nuke_script_node.py has no branch for list/sequence inputs.
• The gizmo builder (nuke_gizmo_builder.py) does not treat image-sequence inputs as
  media inputs, so no Input node would be wired up in the generated gizmo graph.

Acceptance Criteria

• The Annotator panel's _INPUT_ARTIFACT_TYPES includes ImageSequenceArtifact.
• NukeScriptNode adds ImageSequenceArtifact / ListArtifact to the input_types
  of annotated input parameters.
• _artifact_to_path() handles a ListArtifact[ImageUrlArtifact] input: downloads /
  resolves each frame to a local path and returns the printf-style pattern Nuke
  expects (e.g. /tmp/frames/frame.%04d.exr).
• The gizmo builder treats image-sequence inputs as media inputs (wires an Input
  node into the internal graph, similar to VideoUrlArtifact).
• Unit tests cover _artifact_to_path() for the sequence case.
• Integration test (gated on NUKE_EXECUTABLE) verifies a sequence can be passed in
  and read by a Read node inside the script.

Notes

The tricky part is the path-pattern convention: Nuke's Read node expects a printf-style
frame pattern (%04d). When receiving a ListArtifact we need to either:

• download all frames to a temp directory with a consistent naming scheme, or
• require that frame URLs already follow a naming convention we can infer.

The first approach (temp dir with normalised names) is safer and matches how
_artifact_to_path() already handles BlobArtifact → temp PNG.