Sign-up and onboarding flow: from brief to live site

Imported from GitHub issue El-SaMa/lamoi-waas#24 by @El-SaMa.

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Flow

1. Visitor on lamoi.fi (or OMA) picks Site or Shop.
2. Writes a short brief in the TEKORI chat (or picks a starter), sees a free design preview made on nano/cheap settings or a template (decide cost policy).
3. Creates an account and pays (consumer prepay, business may get invoice).
4. Provisioning (El-SaMa/oma#174) + TEKORI build (El-SaMa/tekori#18).
5. Preview, changes by chat, publish; domain step (#6).
6. Welcome email and the tutorial course link.

Tasks

• Cost policy for previews before payment (abuse limits, Turnstile, per-IP caps).
• Screens in OMA and TEKORI, fi + en.
• Analytics of the funnel (sign-up source tracking exists in OMA).

Acceptance criteria

• A test user goes from brief to published site on staging without staff help.

Depends on

El-SaMa/oma#174, El-SaMa/tekori#18, #6.

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Plan key W30. Epic: El-SaMa/lamoi-waas#25.