Transparency and navigation polish
- Public changelog page with a dated history of every major improvement.
- Payment status (Confirmed / Failed / Verifying) now shown consistently across the product page, admin payments and the activity feed.
- Back navigation is context-aware: opening a project from the activity feed returns you to the feed instead of the homepage.
- Project websites are hidden when the latest payment failed and no earlier successful payment exists.
- Rank badges are accurate for every payment state — "Payment failed", "Verifying payment", "Pending review" or "Awaiting payment" instead of a generic label.
- Broken or missing favicons now fall back to a clean letter tile instead of a broken image.