fix(artwork): remove duplicate Duality (Ultrawide) entry

[castrojo]

The duality-ultrawide entry in artwork.json was a duplicate of the existing duality entry (same artwork, same author/credits). Removing to keep the gallery clean.

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com

[gemini-code-assist]

Code Review

This pull request removes the duality-ultrawide entry from the artwork metadata. The review feedback highlights that this removal results in the loss of a nightUrl reference that is missing from the primary duality entry and notes that the entry will likely be re-added by the automated sync script unless the script's skip list is updated.

I am having trouble creating individual review comments. Click here to see my feedback.

static/data/artwork.json (283-297)

Removing the duality-ultrawide entry results in the loss of the nightUrl reference (line 292), which is currently missing from the remaining duality entry (line 320). If these represent the same artwork, the nightUrl should be preserved in the remaining entry to avoid data loss.

Additionally, since scripts/update-artwork.mjs automatically syncs wallpapers based on directory names in the upstream repository, this entry will likely be re-added the next time the script runs. To prevent this, the duality-ultrawide directory should be added to the SKIP_DIRS set in the sync script.