v2.6.3

Dependency refresh release.

- client-go v2.55.1 -> v2.57.0, with the new API surface mirrored into
  the MCP tools: the group Datadog integration now reads the nested
  properties payload and exposes datadog_ci_visibility, and groups
  expose the new root_storage_statistics object.
- All remaining Go modules updated, including golang.org/x/crypto
  v0.55.0 and lipgloss v2.0.6.
- Docs site stack refreshed (pnpm 11.21.0, astro 7.2.1) with the
  dependency audit gate clear.

Verified with the full Docker e2e suite: 1445 tests, 17 skipped, 0
failures.