Protocol landing: the flow is the page

[kgraph57]

Summary

• Replaces the cream/kicker/Replay SaaS landing with a protocol page.
• Quality is shown as the gated loop (claim ledger → engine → semantic → 15-criteria → adversarial → correction) with a visible 5→2 return, cap 3.
• Static vitamin D CLI (T3 stays T3). One install block. EN + JA.

Test plan

• Open https://kgraph57.github.io/evidentia/ after merge — flow rail visible, no Replay, no star CTA
• JA twin at /ja/ — title 品質はどう担保されるか
• Copy button on the install block