- paywall.py: conservative domain-level paywall detection (New Scientist,
Nature, and common hard/soft paywalls). Never fetches pages — an honest hint.
- API: Article gains a 'paywalled' flag; the brief now leads with a gentle AND
readable story (paywalled/charged stories stay in the five, just not first).
- New GET /api/replacement returns the next-best readable, unshown article
(honors mood+prefs via the merged prefs param; gentle=true for hero swaps).
- UI: paywalled cards show 'May need a subscription'; a Replace / 'Find one I
can read' action (always visible, while tuning actions stay tucked) swaps the
card for a readable alternative, with a gentle notice when none remain.
- Tests: paywall detection + replacement behavior (77 total).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
