docs: publish release evidence

[fabiorosa]

What changed

• Publish the verified public demo URL and its free-tier limits.
• Add hosted Render screenshots for the fictional event list and dead-letter detail.
• Mark WOP-305 complete in the executable backlog and update the release handoff.

Evidence

• Render deployment is live at https://afterhook.onrender.com.
• Main Quality runs 31428189159 and 31429084747 passed.
• Twelve consecutive public /health and /v1/demo checks returned 200.
• The fictional retryable-failure scenario reached DEAD_LETTER after three attempts.

The checked-in walkthrough video remains explicitly labeled as local real-process evidence. Two failed hosted video captures are intentionally excluded from this PR.