fix(openapi_fdw): handle RFC 8288 Link header pagination

[codybrom]

Closes #598

Summary

• handle_pagination only inspected JSON-body pagination paths (/links/next, /meta/pagination/next, etc.) and never read the HTTP Link response header. APIs that paginate exclusively via Link — GitHub, GitLab, and most REST services that follow RFC 5988 / RFC 8288 — never auto-paginated past the first page.
• Thread response headers into handle_pagination and parse rel="next" entries before the existing JSON-body lookups. Cross-origin protection is preserved automatically by the existing resolve_pagination_url path.
• Precedence: configured cursor_path → Link header → JSON-body next-URL → has_more + cursor.

Verification

Tested end-to-end against the real GitHub API:

SELECT count(*) FROM repo_pulls
WHERE owner = 'supabase' AND repo = 'wrappers' AND state = 'all';
-- → 468  (vs 30 without the fix, with page_size=30)

Debug trace shows exactly 16 chained HTTP requests, each one following the previous response's Link: <...>; rel="next" header (GitHub even rewrites the path to /repositories/558211706/pulls?...&page=N — the FDW transparently follows it).

Test plan

• 12 new unit tests in response_tests.rs cover: GitHub-style multi-rel headers, case-insensitive header name, unquoted rel values, multi-rel values (rel="next prev"), extra params, no-match returns None, array bodies + Link header, Link beats body autodetect, configured cursor_path beats Link, fallback to body when no rel="next", multiple separate Link headers, malformed input doesn't panic.
• All 89 pre-existing pagination tests still pass.
• Verified end-to-end against real GitHub API (468 PRs, 16 chained requests via Link header).

Docs

• docs/catalog/openapi.md — added Link header to the supported pagination styles list.
• docs/catalog/wasm/index.md — bumped OpenAPI tag/source links from v0.1.4 → v0.2.0 (was stale; main openapi.md already lists 0.2.0 as current).
• wasm-wrappers/fdw/openapi_fdw/examples/github/README.md — added a "Pagination across pages" subsection in §6 with the count(*) demo as a real-world test.

[codybrom]

Note: I did not bump the version on this PR, but can if the change is approved.

[Copilot]

Pull request overview

Adds RFC 8288 Link header support to openapi_fdw pagination so APIs that paginate exclusively via Link: <...>; rel="next" (e.g., GitHub/GitLab) can automatically fetch subsequent pages, while preserving existing pagination behaviors and cross-origin protections.

Changes:

• Thread HTTP response headers into handle_pagination and add Link header parsing (with precedence between cursor_path / header / body heuristics).
• Add unit tests covering a variety of Link header formats and precedence rules.
• Update OpenAPI FDW docs and GitHub example README to document Link header pagination support.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
wasm-wrappers/fdw/openapi_fdw/src/response.rs	Adds Link header parsing helpers and updates pagination precedence to consider RFC 8288 headers.
wasm-wrappers/fdw/openapi_fdw/src/response_tests.rs	Adds/updates unit tests for Link header pagination and new handle_pagination signature.
wasm-wrappers/fdw/openapi_fdw/src/request.rs	Passes response headers into pagination handling at request time.
wasm-wrappers/fdw/openapi_fdw/examples/github/README.md	Documents GitHub pagination behavior and provides a multi-page count(*) example.
docs/catalog/wasm/index.md	Updates OpenAPI Wasm wrapper tag/source links to v0.2.0.
docs/catalog/openapi.md	Documents Link header pagination as a supported pagination style.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[burmecia]

Thanks for the PR!