v1.4.0

Adds a pages sub-package: a Go 1.23 range-over-func iterator for
Link-header pagination, plus a typed wrapper that decodes each page
into elements of any type. The iterator runs on a caller-supplied
*http.Client, so the existing RateLimit, Throttle, Retry, oauth2,
and ETag layers apply per page with no extra wiring. Also extends
ghtest with a LinkHeader fixture builder so tests can construct
RFC 8288 Link headers without rolling their own. No new runtime
dependencies in the root module.

Added

• pages.Pages(ctx, client, method, url, headers): range-over-func
  iterator over paginated REST responses. Walks Link: rel="next"
  and yields each *http.Response. Caller drains and closes each
  body. Errors stop iteration after one yield; a clean end of
  pagination (no rel="next") stops silently.
• pages.As[T any](ctx, client, method, url, headers): typed wrapper
  that decodes each page into []T with the standard library JSON
  decoder and yields elements one at a time. Iterator owns each
  response body and closes it after decoding, including on caller
  break and on context cancellation. T has no constraint, so
  *github.Repository and similar SDK types work without
  implementing json.Unmarshaler.
• pages.ErrInvalidLinkHeader: exported sentinel surfaced when a
  response Link header is structurally malformed. A missing
  rel="next" is treated as a clean end of pagination, not an error.
• ghtest.LinkHeader(baseURL, page, perPage, lastPage): builds an
  RFC 8288 Link header value for fixture servers. Returns "" when
  lastPage <= 1 so handlers can branch on a single string. Pairs
  with ghtest.Write304IfMatch and ghtest.WriteSecondaryLimit.

Documentation

• doc.go adds a paragraph naming the pages sub-package alongside
  the existing etag, ratelimit, and throttle notes.
• README.md adds an "Iterating over paginated results" recipe under
  the Recipes section, with a runnable snippet using pages.As plus
  WithETagCache.
• TESTING.md replaces the manual Link-header pagination recipe with
  one that uses ghtest.LinkHeader, mirroring how the
  secondary-rate-limit recipe references ghtest.WriteSecondaryLimit.
• examples/README.md adds the list-all-repos/ row to the table.

Examples

• New examples/list-all-repos/: uses pages.As[*github.Repository]
  to walk /user/repos against api.github.com end to end. Shows
  the iterator composing with WithETagCache and WithUserAgent.

Dependencies

No changes in the root module. The examples/ module is unchanged.

Tooling

• .golangci.yaml: bodyclose added to the test-file linter
  exclusion list. The iter.Seq2 yield-then-close pattern in
  pages_test.go produces false positives the linter cannot trace
  through; the suppression is scoped to _test.go paths so production
  code still gets full bodyclose coverage. The two //nolint:bodyclose
  directives in pages/pages.go remain (caller-closes contract on
  yielded responses; close-via-decodePage on the typed wrapper).