Add post-subscribe follow-ups and fix subscribe success feed links master
The atproto and email success modals now share a SubscribeSuccess frame with follow-up actions: share the publication on Bluesky (via a lazily loaded composer and a shared BskyPostSubmit) and recommend it from one of the viewer's own publications. Subscribe/unsubscribe writes are mirrored into the cached identity (viewerSubscription helpers) so every subscribe surface on a page flips together instead of refetching identity. The "Get the RSS Feed" and "Pin Custom Feed in Bluesky" links on the atproto success screen had empty hrefs; they now point at the publication's /rss feed and the Bluesky subscribed-publications feed, sharing that URL with the manage-subscription panel. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013tYNJvzxvce46Kwo1QN1oq