Refactor URL sanitization: shared helper, space-only encoding, robust test

[Copilot]

Three reviewer feedback items from the geothermal extraction PR addressed:

• Shared _sanitize_url — extracted to compass/web/url_utils.py; both compass/scripts/download.py and compass/web/website_crawl.py import from there, eliminating duplicated logic that could drift.

• Simplified encoding — replaced quote(unquote(path), safe="/") + query re-encoding with a targeted path.replace(" ", "%20"). The original approach could corrupt presigned/SAS URLs or alter semantically significant query parameters. Query string and existing percent-encoding are now left untouched.

# before — full unquote/requote round-trip, query string re-encoded
safe_path = quote(unquote(parsed.path), safe="/")
safe_query = urlencode(parse_qsl(parsed.query, keep_blank_values=True), doseq=True)

# after — only fixes literal spaces in path, everything else preserved
safe_path = path.replace(" ", "%20") if " " in path else path
# parsed.query passed through unchanged

• Test robustness — added assert len(links) == 1 before next(iter(links)) in test_extract_links_from_html_sets_text_from_anchor to avoid silent false-passes if _extract_links_from_html returns an unexpected number of results.

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 55.53%. Comparing base (bac918c) to head (6c6e950).
⚠️ Report is 1 commits behind head on feature/geothermal-extraction-pr.

Additional details and impacted files

@@                         Coverage Diff                          @@
##           feature/geothermal-extraction-pr     #401      +/-   ##
====================================================================
+ Coverage                             55.44%   55.53%   +0.09%     
====================================================================
  Files                                    61       62       +1     
  Lines                                  5699     5695       -4     
  Branches                                534      534              
====================================================================
+ Hits                                   3160     3163       +3     
+ Misses                                 2491     2485       -6     
+ Partials                                 48       47       -1     

Flag	Coverage Δ
unittests	55.53% <100.00%> (+0.09%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.