Digital products & multi-format creator commerce

Why / Context

Teardown STEAL (Euron Systems): multi-format creator commerce — digital downloads, 1:1 sessions, bundles — is "more revenue per creator on infrastructure you're building anyway — low incremental engineering cost." The commerce engine, cart, and ledger already treat DIGITAL_PRODUCT as a first-class item type; this issue ships the surfaces.

Schema already in place — NO migration required

• DigitalProduct (kind EBOOK/TEMPLATE/DATASET/OTHER, fileAsset or externalUrl, publish status/visibility)
• CommerceItemType.DIGITAL_PRODUCT across Price/CartItem/OrderItem + ledger/commission snapshots
• 1:1 sessions ship via issue #19 (MentorOffering); bundles via issue #16 — this issue is downloads + storefront integration

Implementation plan

1. Studio: digital product CRUD (title/slug/description/kind), file upload to Supabase Storage uploads bucket (private) via MediaAsset, pricing rows, publish flow through the same moderation queue as courses.
2. Delivery service (src/lib/commerce/downloads.ts): fulfillment marks the OrderItem FULFILLED; buyer library page lists purchases; downloads served via short-lived signed URLs (per-request), watermark PDF option (buyer email footer) for EBOOK kind.
3. Storefront/catalog: digital products section on storefronts + marketplace category filter; reviews reuse pattern deferred (CatalogReview extension noted as future-additive per gap review).
4. Refund policy: digital goods default refundWindowDays=0 or first-download-voids (policy in PlatformConfig; snapshot per OrderItem as usual) — stated at purchase.
5. Anti-leak basics: signed URLs, download-count soft limits, watermarking; DRM explicitly out of scope for downloads.
6. Free lead magnets: price 0 path (email-gated "purchase" creating a FREE payment) for funnel use (pairs with issue #7).
7. Creator analytics: downloads/revenue in studio dashboard (issue #12).

Acceptance criteria

• Creator publishes an ebook; buyer purchases and downloads via expiring signed URL
• Watermarked PDF carries buyer identifier
• Library page lists all digital purchases with re-download
• Zero-price lead magnet captures email and fulfills without payment provider round-trip
• Commission/ledger entries identical in shape to course sales

Dependencies / sequencing

• MVP M7 fulfillment + M4 storage; issues #16/#19 complete the multi-format trio

Start with src/lib/commerce/downloads.ts and trace the existing fulfillment, storage, storefront, and studio flows described in the issue. Use the existing DIGITAL_PRODUCT commerce records and PlatformConfig refund policy as entry points; done means the listed purchase, delivery, watermarking, library, free-lead-magnet, and ledger acceptance criteria work together.