Stop VF hydrator from ignoring original-tweet verdicts on retweets

[Pitchfork-and-Torch]

Bug

Phoenix VFCandidateHydrator and Following VFFollowingCandidateHydrator fetch the retweet original, then stamp visibility_reason from the wrapper id.

The original is already in the VF map: For You pushes retweeted_tweet_id into the TimelineHome batch; Following pushes it into the same Home batch. Lookup is all_results.get(&candidate.tweet_id).

TimelineHome NSFW-high-precision is Interstitial, not Drop. VFFilter only hard-drops Action::Drop. should_drop_ancillary also ignores Interstitial. The original verdict never reaches the card.

OON retweets are already dropped by OONRetweetReplyFilter. This path is a followed-user retweet of an interstitial original.

• Entry: VFCandidateHydrator / VFFollowingCandidateHydrator (both already fetch the original)
• Sink: visibility_reason forwarded on the scored post (scored_posts_server.rs); VFFilter keeps Interstitial
• Break: primary lookup keyed by wrapper tweet_id instead of retweeted_tweet_id.unwrap_or(tweet_id)
• Viewer effect: in-network retweet of NSFW / gore original serves with no sensitive-media interstitial
• Twin: AdsBrandSafetyVfHydrator primary_id is already retweeted_tweet_id.unwrap_or(tweet_id)

This is not PR 55 / 90 (Home vs Recs merge). This is not PR 115 (Following quotes at Recs). This is not PR 116 (OON RT originals at Recs; those wrappers are dropped before VF). This is not PR 118 (QuoteHydrator TES key).

Fix

Look up the primary VF verdict with primary_vf_id = original tweet id. Native posts unchanged. Ancillary Drop on the original is unchanged.

Tests

• Native post still uses its own id
• Retweet of an Interstitial original stamps Interstitial (fails on unmodified main)
• Wrapper-only Interstitial is not used as the primary
• Original Drop still ancillary-drops

cargo: cannot run. Public dump has no Home Mixer manifest.

[Pitchfork-and-Torch]

Parking this intern-stack PR per operator GitHub cleanup (2026-09-08). Hunt notes remain local. Not a reject of the class.

[Pitchfork-and-Torch]

Reopened. This was a serving-path hunt PR parked by mistake during the 2026-09-08 intern-stack cleanup. Not a reject of the class. Leaving it for xAI review.

[Pitchfork-and-Torch]

Rebased onto current xai-org main. Kept primary_vf_id lookup and wired it through upstream visibility_fields so retweet wrappers still inherit the original tweet verdict.