feat(techreport): add experimental soft navigation Core Web Vitals

[max-ostapenko]

Description

Extends the Technology Report frontend on httparchive.org to support the newly available CrUX experimental soft navigation Core Web Vitals metrics starting with the September 2026 dataset (web.dev blog).

• Adds overall_sn, LCP_sn, CLS_sn, and INP_sn to cwv_subcategories, cwv_thresholds, and display labels.
• Adds histogram bucket configs in cwv_distribution.metric_config for LCP_sn, INP_sn, and CLS_sn using *_sn_origins.
• Exposes metrics across Drilldown and Comparison timeseries selectors.
• Adds soft navigation columns to the Geographic Breakdown table.
• Verified with Astro build (all 46 pages built cleanly, internal links valid).

Closes #1372

[github-actions]

Visit the preview URL for this PR (updated for commit 46413b4):

https://httparchive--pr1373-feat-crux-softnavs-pk00snpp.web.app

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[max-ostapenko]

@tunetheweb do we also need this for metric's histograms?

[tunetheweb]

Thanks! Looking good, though I'm not seeing the data on the test site:

@tunetheweb do we also need this for metric's histograms?

Yes ideally. Not sure they're used much, but ideally we'd have the exact same functionality!

[max-ostapenko]

@tunetheweb cache?

It's also just one point, so you need to hover over it to find it

The line will appear next month.

I don't think it's worth adding point markers just for this.

[tunetheweb]

I think it must be a cache issue. Cause if you look you can see I also see undefined in the big number below the heading whereas your screenshot doesn’t show that.

[max-ostapenko]

Good call on the metric labels. Cleaned up display_name.
Also found a way to add point marker for series with only 1 data point (length === 1).

For the histograms - ready in HTTPArchive/tech-report-apis#168

[tunetheweb]

Changing to a different technology shows results for me. Does ALL work for you?

[max-ostapenko]

Cleaned cache

[tunetheweb]

Can we exclude rows where the date is N/A?

[tunetheweb]

Looking real good now!

I wonder if it would be possible to add a toggle to show soft nav data on CWV/LCP/CLS/INP charts as additional data points to allow for easy comparison of how much they will change when these become stable and replace the old definitions (currently planned for May 2027)?

That would be easier than toggling back and forth (especially at the moment when there data points don't line up).

Note I'd keep the current functionality AS WELL so you can see table, country and histograms.

[max-ostapenko]

Added as a dashed line on the main CWV metrics.

[max-ostapenko]

BTW In May 2027 release I assume the main metrics will just get the softnav values, so the transition will be just to rollback all the changes from this PR.

[tunetheweb]

Added as a dashed line on the main CWV metrics.

I like it! But worry it could get very noisy to have this on by default, especially in the comparison view. WDYT about reverting the overlay in the default view, and changing the soft nav view to show both instead?

BTW In May 2027 release I assume the main metrics will just get the softnav values, so the transition will be just to rollback all the changes from this PR.

That's correct, though we've some small changes we'd wanna keep (excluding N/A from table, diabling histogram view in CWV view).

[max-ostapenko]

So skipped toggle, added both types on the soft nav charts to focus on the comparison right away.
Have a look please.

[tunetheweb]

LGTM!

Great work and thanks for getting this together so quickly.