[PRIVACY]: Implement account export, deletion, and retention workflows

[barry01-hash]

Context

User data spans authentication, profiles, wallet addresses, payouts, applications, comments, support tickets, logs, and storage objects. Account deletion cannot be a single row delete because financial/audit records may require retention while personal data should be removed or anonymized.

Scope

• Inventory personal data and define retention/legal basis by model and storage object type.
• Build authenticated export generation with a versioned machine-readable manifest.
• Implement staged deletion: request, re-authentication, cooling-off, cancellation, execution, and completion receipt.
• Anonymize retained financial/audit records while preserving referential integrity.
• Delete/revoke storage objects, auth identities, sessions, and downstream data through durable jobs.
• Ensure backups and analytics are covered by documented retention behavior.

Acceptance criteria

• Export contains all user-linked data and is available through an expiring private download.
• Deletion is idempotent, resumable, and auditable without retaining unnecessary PII.
• Active financial/escrow obligations block or defer deletion with a clear reason.
• Automated tests cover every related model and partial-failure recovery.
• Retention rules are configuration-backed and documented.
• Privacy UI clearly communicates scope, timing, and irreversible effects.

Relevant areas

Prisma models, Supabase Auth/Storage, PostHog, email, profile/settings UI, background jobs.