5b: connected users get a 'Summarize any video' URL input on the feed; submit
posts to /paste (HTMX) and swaps the resulting card / inline error into the feed.
7: the connect flash now sets expectations for the async onboarding burst —
'finding your subscriptions, your newest videos will appear below as summarized'.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Pure parser for watch?v=, youtu.be/, shorts/, embed/, and bare ids; rejects
non-YouTube hosts and malformed input. Foundation for paste-a-URL summarize
(Feature 2). No fetch, no gate interaction — parsing only.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>