Phase 7: OCI delete path for manifests and blobs

Manifest delete (DELETE /v2/<name>/manifests/<digest>): rejects tag
references with 405 UNSUPPORTED per OCI spec, cascades to tags and
manifest_blobs via ON DELETE CASCADE, returns 202 Accepted.

Blob delete (DELETE /v2/<name>/blobs/<digest>): removes manifest_blobs
associations only — blob row and file are preserved for GC to handle,
since other repos may reference the same content-addressed blob.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

PROGRESS.md

@@ -6,7 +6,7 @@ See `PROJECT_PLAN.md` for the implementation roadmap and
 
 ## Current State
 
-**Phase:** 6 complete, ready for Phase 7
+**Phase:** 7 complete, ready for Phase 9
 **Last updated:** 2026-03-19
 
 ### Completed
@@ -18,6 +18,7 @@ See `PROJECT_PLAN.md` for the implementation roadmap and
 - Phase 4: Policy engine (all 4 steps)
 - Phase 5: OCI pull path (all 5 steps)
 - Phase 6: OCI push path (all 3 steps)
+- Phase 7: OCI delete path (all 2 steps)
 - Phase 8: Admin REST API (all 5 steps)
 - `ARCHITECTURE.md` — Full design specification (18 sections)
 - `CLAUDE.md` — AI development guidance
@@ -26,14 +27,51 @@ See `PROJECT_PLAN.md` for the implementation roadmap and
 
 ### Next Steps
 
-1. Phase 7 (OCI delete)
-2. After Phase 7, Phase 9 (garbage collection)
-3. Phase 10 (gRPC admin API)
+1. Phase 9 (garbage collection)
+2. Phase 10 (gRPC admin API)
 
 ---
 
 ## Log
 
+### 2026-03-19 — Phase 7: OCI delete path
+
+**Task:** Implement manifest and blob deletion per OCI Distribution Spec.
+
+**Changes:**
+
+Step 7.1 — Manifest delete:
+- `db/delete.go`: `DeleteManifest(repoID, digest)` — deletes manifest
+  row; ON DELETE CASCADE handles manifest_blobs and tags
+- `oci/delete.go`: `handleManifestDelete()` — policy check
+  (registry:delete), rejects deletion by tag (405 UNSUPPORTED per OCI
+  spec), returns 202 Accepted, writes `manifest_deleted` audit event
+- Updated `oci/routes.go` dispatch to handle DELETE on manifests
+
+Step 7.2 — Blob delete:
+- `db/delete.go`: `DeleteBlobFromRepo(repoID, digest)` — removes
+  manifest_blobs associations only; does NOT delete the blob row or
+  file (GC's responsibility, since other repos may reference it)
+- `oci/delete.go`: `handleBlobDelete()` — policy check, returns 202,
+  writes `blob_deleted` audit event
+- Updated `oci/routes.go` dispatch to handle DELETE on blobs
+- Extended `DBQuerier` interface with delete methods
+
+**Verification:**
+- `make all` passes: vet clean, lint 0 issues, all tests passing,
+  all 3 binaries built
+- DB delete tests (5 new): delete manifest (verify cascade to tags and
+  manifest_blobs, blob row preserved), manifest not found, delete blob
+  from repo (manifest_blobs removed, blob row preserved, manifest
+  preserved), blob not found, blob exists globally but not in repo
+- OCI delete tests (8 new): manifest delete by digest (202), delete by
+  tag (405 UNSUPPORTED), manifest not found (404 MANIFEST_UNKNOWN),
+  repo not found (404 NAME_UNKNOWN), cascading tag deletion verified,
+  blob delete (202), blob not in repo (404 BLOB_UNKNOWN), blob delete
+  repo not found
+
+---
+
 ### 2026-03-19 — Phase 6: OCI push path
 
 **Task:** Implement blob uploads (monolithic and chunked) and manifest