fix(mcp): document select_columns valid fields and URL scheme for preview tools

[aminghadersohi]

Summary

• get_dataset_info / select_columns: The field description did not list which values are valid. Updated both GetDatasetInfoRequest.select_columns and the function docstring to enumerate the default set and all additional available field names so the model can construct a working call from the schema alone.

• URL scheme for preview/link tools: get_chart_preview, generate_explore_link, update_chart_preview, and open_sql_lab_with_context did not document the URL scheme of their returned URLs. Added a note that the scheme mirrors the configured instance URL (HTTPS in production/staging, HTTP in local development). Also updated URLPreview.preview_url field description.

Testing

• Changes are docstring/schema description only — no logic changes
• Pre-commit passes

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.41%. Comparing base (2bd9ab4) to head (feed525).
⚠️ Report is 16 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #41595      +/-   ##
==========================================
- Coverage   64.43%   64.41%   -0.02%     
==========================================
  Files        2667     2668       +1     
  Lines      147073   147220     +147     
  Branches    33939    33954      +15     
==========================================
+ Hits        94765    94838      +73     
- Misses      50593    50666      +73     
- Partials     1715     1716       +1     

Flag	Coverage Δ
hive	39.09% <100.00%> (+<0.01%)	⬆️
mysql	57.65% <100.00%> (-0.01%)	⬇️
postgres	57.72% <100.00%> (-0.02%)	⬇️
presto	40.64% <100.00%> (+<0.01%)	⬆️
python	59.13% <100.00%> (-0.02%)	⬇️
sqlite	57.35% <100.00%> (-0.01%)	⬇️
unit	100.00% <ø> (ø)

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

☔ View full report in Codecov by Harness.
📢 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.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[rebenitez1802]

LGTM

[bito-code-review]

Bito Automatic Review Skipped – PR Already Merged

Bito scheduled an automatic review for this pull request, but the review was skipped because this PR was merged before the review could be run.
No action is needed if you didn't intend to review it. To get a review, you can type /review in a comment and save it