feat: update controls in the admin, release token scope, build info in CI images [CI]

The versions page shows each node's update state with update buttons, API
tokens get a release scope that can only register releases (used by CI), and
the CI image and release builds now pass the tag, commit and build time.

docs/api.md

@@ -130,7 +130,7 @@
 | GET | `/api/admin/raw/chunks/{chunk_id}` | 下载原始块（`application/vnd.monitor.rawchunk`）；过期返回 410 `raw_expired` |
 | GET | `/api/admin/events?agent_id=&kind=&from=&to=` | 事件 |
 | GET | `/api/admin/analysis/recompute` | 指标重算进度 |
-| GET/POST/DELETE | `/api/admin/api-tokens` | 作用域为 `read` 或 `admin`；明文只显示一次 |
+| GET/POST/DELETE | `/api/admin/api-tokens` | 作用域为 `read`、`admin` 或 `release`（只能登记发布清单，给 CI 用，什么都读不了）；明文只显示一次 |
 | GET | `/api/admin/releases` | 各应用、各通道的当前版本，以及节点的版本分布（由 `Fleet.Server.Releases` 提供） |
 | POST | `/api/admin/releases/{app}/{channel}/rollout` | `{version, batches:[{labels?, count?}], soak_minutes}`：分批灰度；只能选择已经签名的清单 |
 | POST | `/api/admin/releases/{app}/approve` | 对 `policy = notify` 的节点批准更新 `{version, agents?}` |