`44ae6e1`

changelog: note §2 follow-ups (README + topics + merge-upstream)

Authored by mfwolffe <wolffemf@dukes.jmu.edu> yesterday

Status	File	+	-
M	`CHANGELOG.md`	15	0

CHANGELOG.mdmodified

    this REST surface lands first so operators have an audit + purge
    seat for when caches arrive.
  - **Capability:** `actions-caches` added to `/api/v1/meta`.
 +- **REST: repos follow-ups (S50 §2 closure).**
 +  `GET /api/v1/repos/{o}/{r}/readme[?ref=]` returns the repo's
 +  README as a base64-encoded blob with `download_url` for the raw
 +  bytes (capped at 1 MiB to match the HTML render cap; prefers
 +  `.md`/`.markdown` over plain text when multiple READMEs exist).
 +  `PUT /api/v1/repos/{o}/{r}/topics` and
 +  `DELETE .../topics` replace and clear the topic set atomically
 +  (server-side normalization: lowercase, dedup; constraints: max
 +  20, 1–50 chars of `[a-z0-9-]`). `POST .../merge-upstream`
 +  fast-forwards a fork's default branch to its upstream — refuses
 +  non-forks with 422 and divergent forks with 409 (users must
 +  reconcile locally). Scopes: `repo:read` on README,
 +  `repo:write` on topics and merge-upstream.
 +- **Capabilities:** `readme`, `topics`, `merge-upstream` added to
 +  `/api/v1/meta`.
  ### Added (internal)