[autofix] pixiv/download: full artwork URL rejected

Summary

OpenCLI autofix repaired this adapter locally, and the retry passed.

Adapter

• Site: pixiv
• Command: pixiv/download
• OpenCLI version: 1.8.6

Original failure

• Error code: COMMAND_EXEC

Invalid illustration ID: https://www.pixiv.net/artworks/141704294

Root cause

The positional argument was validated as digits only even though users commonly provide canonical Pixiv artwork URLs.

Local fix summary

Normalize either a numeric ID or a trusted pixiv.net/artworks/<id> URL to the numeric illustration ID before calling /ajax/illust/<id>/pages. Invalid values now raise ArgumentError.

Verification

The full URL downloaded all 10 pages successfully. All files were valid 1536x1536 JPEG images, totaling about 3.9 MB. opencli validate pixiv/download passed.