Resolve relative inline links to fully-qualified URLs during scrape - #129

Summary

Closes #12

When scraping documentation pages, relative <a href> links in the source HTML (e.g. /self-hosted/latest/migration/entire-database/) were carried verbatim into the generated markdown. Per the issue, this produces broken-looking inline links when an LLM quotes the returned markdown chunks, since the link target isn't resolvable without the source page's base URL.

This resolves relative links against the HTML source (per the issue's suggestion), before the markdown conversion step, across all three ingest pipelines:

• ingest/tiger_docs.py — new resolve_relative_links method on SitemapMarkdownSpider, called in parse() with the current page's response.url as the base, right after the existing strip_data_images step.
• ingest/postgis_docs.py — calls the new shared resolve_relative_links util with each page's resolved full_url as the base.
• ingest/postgres_docs.py — calls the same shared util with a per-page URL built from POSTGRES_BASE_URL, the version, and the page's slug (threaded version into build_markdown, which didn't have it before).
• ingest/utils/beautiful_soup.py — adds the shared resolve_relative_links(soup, base_url) helper (urljoin was already imported here but unused).

Already-absolute links, mailto:/tel: links, etc. are left untouched by urljoin.

Note: this also expands #fragment-only anchors (same-page links) to fully-qualified URLs, since urljoin treats them like any other relative reference. The targets are correct, and it's arguably desirable in a standalone markdown corpus, but PostgreSQL/PostGIS docs are anchor-heavy, so it will visibly increase diff volume in the regenerated output — flagging so it's not a surprise.

Test plan

No Python test harness exists in this repo (ingest/ has no test files and CI (.github/workflows/test.yml) only runs bun test), so I verified behavior manually against the exact example from the issue:

$ cd ingest && PYTHONPATH=.. uv run python - <<'PY'
from bs4 import BeautifulSoup
from markdownify import markdownify
from ingest.utils.beautiful_soup import resolve_relative_links

html = '<main><a href="/self-hosted/latest/migration/entire-database/">migrate your entire database at once</a></main>'
soup = BeautifulSoup(html, "html.parser")
soup = resolve_relative_links(soup, "https://docs.tigerdata.com/self-hosted/latest/migration/some-page/")
print(markdownify(str(soup), heading_style="ATX").strip())
PY
[migrate your entire database at once](https://docs.tigerdata.com/self-hosted/latest/migration/entire-database/)

• Confirmed relative links resolve to fully-qualified URLs, matching the issue's before/after example
• Confirmed already-absolute links and same-page fragment links are handled correctly by urljoin
• uvx ruff check . / uvx ruff format --check . show no new issues introduced by this change (diffed against main, all remaining warnings pre-exist on main)
• python -m ast parses all four changed files without error

🤖 Generated with Claude Code