feat: enable marketing site registration and launch-prompt preservation (T12)

BETA_LAUNCH_PLAN.md

@@ -8,6 +8,10 @@
 >
 > **Drafted:** 2026-04-30. **Owner:** Mark + AI.
 >
+> **Scope note for AI:** this plan is about the **vibnai.com web product** beta — it is *not* the `vibn-code`
+> desktop thin-client effort (that's `VIBNCODE_THIN_CLIENT_CHANGES.md`). Treat dates/phases as historical;
+> verify status against the codebase before acting.
+>
 > **Scope:** Everything we agreed in the 2026-04-30 review that's NOT already
 > shipped. Pulls in the unfinished items from Path B (DNS, cert, previews,
 > eval) AND the "before strangers see this" gaps that Path B doesn't cover