release(slice4): v0.50.0 — single-entry metadata edit + sidecar-aware writes (§22.4a SLICE-4)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -23,6 +23,51 @@ skip versions are the composition of each intervening adjacent
 release's steps in order — no A-to-B path is pre-computed beyond
 that.
 
+## 0.50.0 — 2026-06-07
+
+**Minor — single-entry metadata edit + sidecar-aware writes (§22.4a SLICE-4).**
+An authorized user can now edit one entry's schema-defined metadata directly from
+its detail view. A new endpoint
+`POST /api/projects/{id}/collections/{cid}/rfcs/{slug}/meta` takes `{values:{…}}`,
+validates them against the collection's `fields:` schema at the write boundary
+(INV-4), writes them to the entry's `<slug>.meta.yaml` **sidecar** with a **direct
+commit** (D7 — no PR for authorized roles), and re-ingests. A legacy entry is
+**lazy-migrated** to a clean body-only `.md` + sidecar on its first metadata edit.
+The detail view renders one control per declared field (enum→select, tags→chips,
+text→input), read-only without contribute access; `GET` on an entry now returns
+its `meta` mapping and a `can_edit_meta` capability. This completes PUC-1 of the
+[Configurable Collection Metadata](./docs/design/2026-06-06-configurable-collection-metadata.md)
+design (§7.2); bulk edit (SLICE-5) follows.
+
+Carried from SLICE-1: **every entry write path is now sidecar-aware.** Graduation,
+ownership claim, retire/un-retire, mark-reviewed, the body-edit accept/flush
+wrappers, and the PR-replay wrappers all dual-read an entry (so a migrated
+body-only `.md` no longer crashes `entry.parse`) and write metadata changes to the
+sidecar, keeping the `.md` body pure (INV-2) and never re-growing frontmatter; a
+legacy entry lazy-migrates on its first metadata-bearing write. With the write
+paths safe, the **Owner-gated collection-migration endpoint**
+`POST /api/projects/{id}/collections/{cid}/migrate` now ships (PUC-5): it converts
+a collection's legacy-frontmatter entries to clean body-only `.md` + sidecars in
+one commit, idempotently.
+
+Non-breaking and opt-in (INV-5): a collection with **no `fields:`** exposes no
+edit panel and the edit endpoint returns 422 ("no editable fields"); the §22.13
+default `document` collection declares none — so **N=1 deployments see no change**.
+
+**Upgrade steps**
+
+- No schema migration. The edit and migrate endpoints are additive; the sidecar
+  storage layer (mig 033) and `meta_json` index (mig 034) shipped in 0.47.0/0.49.0.
+- A deployment adopts single-entry editing by declaring an `enum`/`tags`/`text`
+  `fields:` block in a collection's `.collection.yaml` (SLICE-2). Contributors+
+  on that collection (§22 Part B / S3 scope roles) may then edit from the detail
+  view; the change is a direct commit to the entry's sidecar.
+- Operators MAY run `POST …/collections/{cid}/migrate` (collection Owner only) to
+  convert a collection's existing entries to clean body-only docs + sidecars up
+  front. It is idempotent and safe to re-run; dual-read means an un-migrated
+  collection keeps working, and entries lazy-migrate on their first metadata edit
+  regardless. **No data migration is required.**
+
 ## 0.49.0 — 2026-06-07
 
 **Minor — faceted left-pane filtering (§22.4a SLICE-3).** A collection that