The native client split the feed on `<div class="post is-shown`, but `is-shown`
is added by SubscribeStar's infinite-scroll JS when a post scrolls into view —
present in a browser-SAVED page (what the Step-0 characterization used) but
ABSENT from the raw server HTML we and gallery-dl actually fetch. So the live
feed (cheunart) parsed to zero posts and raised a false SubscribeStarDriftError.
Align with gallery-dl's proven `_pagination`: split on the generic
`<div class="post ` (trailing space rules out the hyphenated post-content/
post-date/post-body siblings). Also mirror gallery-dl's redirect-based gating
detection (/verify_subscriber, /age_confirmation_warning => auth, not drift).
Regression tests: raw server markup without is-shown now parses; an age-wall
redirect raises SubscribeStarAuthError.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The XHR fix worked (we now get a real 93KB HTML page, not JSON) but cheunart
still drifts — we're being served a full HTML page that isn't the feed. Add
_describe_page(): the drift error now reports the page <title> + which known
interstitial it resembles (cloudflare/bot-challenge, age-gate, login, captcha),
so the next run names the actual cause instead of "markup changed". Strong
suspicion: a Cloudflare challenge (python-requests has no JS; cf_clearance is
UA-locked and our hardcoded UA likely differs from the cookie-capturing browser).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
bvandeusen