docs adr 010 private object evidence

ADR-010: Private object storage and frozen validated evidence

Status: Adopted for planning. Date: 2026-09-28. Scope: planned platform; implementation evidence required by roadmap gates.

Context

Photos can be large, private and hostile; a presigned upload URL can be reused before expiry.

Decision

Private S3-compatible storage/R2; direct bounded-quota upload to quarantine; worker validates exact downloaded snapshot and writes sanitized bytes to a different server-only key. DB stores metadata. Short admin download authorization, lifecycle and orphan sweep.

Alternatives

Store blobs in PostgreSQL; API proxy all photos; public bucket; trust client Content-Type/HEAD alone.

Consequences

Object/DB reconciliation is necessary; bandwidth abuse remains bounded by issuance quotas. Server validation processing still consumes resources. Emulators do not replace actual R2 integration tests.

Validation and follow-up

Use the owning tasks in ROADMAP, specifications in docs index and decision log. Record tested policy/tool versions before marking a release gate complete.