Storage layer

Object/blob storage is a separate composition layer from relational backend and third-party integrations.

packages/core/src/storage/          apps/web/src/storage/
├── blob-ports.ts (IBlobStore)      ├── config.ts           ← BLOB_PROVIDER, R2, tiering knobs
└── (Phase 1: registry, tiering)    ├── wire-storage.ts     ← composition helper
                                    └── providers/
                                        supabase/           ← default today
                                        s3/                 ← Phase 1: R2 + MinIO
                                        tiered/             ← Phase 1: hot/cold facade

How it fits

Layer	Responsibility	Env prefix
backend/	Postgres repos, auth session, admin	NEXT_PUBLIC_BACKEND_PROVIDER
storage/	Files: images, artifacts, vault assets	BLOB_PROVIDER (server), NEXT_PUBLIC_BLOB_PROVIDER (browser), R2_*, BLOB_COLD_*
integrations/	Zotero, GitLab, Mattermost, …	NEXT_PUBLIC_*_PROVIDER

Feature code uses IBlobStore via PaperImageStore — never Supabase Storage SDK directly.

Docs

• ../plans/completed/migration-plan.md — phased self-host (Postgres + tiered blobs, Supabase Auth)
• tiering.md — R2 hot → OCI cold eviction formula
• r2-setup.md — enable R2, create bucket, API token, env vars

Default today

BLOB_PROVIDER=supabase (or unset) → SupabaseBlobStore wired from wire-supabase-backend via wireStorage().

Phase 1 target

BLOB_PROVIDER=tiered → TieredBlobStore (R2 hot, MinIO cold, blob_objects registry).