SABnzbd compat: change_cat/change_script only accept a single nzo_id

[thedancingdeveloper]

Summary

Real SABnzbd's change_cat (and change_script) accept a comma-separated list of nzo_ids in value, applying the change to all of them:

# sabnzbd/api.py:406-416
def _api_change_cat(name, kwargs):
    """API: accepts value(=nzo_id), value2(=category)"""
    nzo_ids = clean_comma_separated_list(kwargs.get("value"))
    cat = kwargs.get("value2")
    if nzo_ids and cat:
        if is_none(cat):
            cat = None
        result = sabnzbd.NzbQueue.change_cat(nzo_ids, cat)
        return report(keyword="status", data=bool(result > 0))
    ...

What rustnzb does instead

handle_change_cat (crates/nzb-web/src/sabnzbd_compat.rs) treats req.value as a single job ID (strip_prefix("SABnzbd_nzo_") + exact/prefix match), so a comma-separated multi-ID value never matches any job and the category change silently fails for all of them. handle_rename has the same single-ID assumption (real SABnzbd's mode=queue&name=rename is single-ID only per job, so that one is fine — but is tracked separately under #72 since it's not reachable via the real endpoint at all).

Impact

A client changing category for multiple selected jobs at once (e.g. bulk re-categorize in a queue UI) fails silently.

Fix

Parse value as a comma-separated list of nzo_ids in handle_change_cat/handle_change_script-equivalent handlers and apply the category to each.