Read changedetection.io watches

cdio handles the base URL and API key. It is GET-only, so nothing here can disturb a running watch. Mutations belong in the web UI.

cdio watches                  # one line per watch, most recently changed first
cdio search "<query>"         # same table, filtered by URL or title
cdio diff <uuid>              # previous -> latest, plain text, changed lines only
cdio history <uuid>           # snapshot timestamps to feed to diff or snapshot
cdio snapshot <uuid> [ts]     # full body of one snapshot, defaults to latest
cdio systeminfo               # queue depth, uptime, watch count

Start from cdio watches (or cdio search when the user names a specific site) to turn whatever they said into a uuid. Then cdio diff <uuid> for what actually moved.

Diffs prefix removed lines with (removed) and added lines with (added). They arrive unfiltered, so a page with a rotating ad slot or a timestamp in the footer produces real diffs full of noise. Read the diff and report the substantive change, not every line of it.

Two flags to know: P in the watches table means the watch is paused and its last_checked is stale, M means notifications are muted so a change there fired no alert.

If cdio exits non-zero, report the error. A 403 means the API key is wrong or missing, a 404 on a diff usually means the watch has only one snapshot so there is nothing to compare yet, and a credentials error names the chezmoi apply to run.