Add Blueprint details step to blueprint selection flow

[ivan-ottinger]

Related issues

• Resolves STU-1196

Proposed Changes

• Add a "Blueprint details" intermediate step to the manual blueprint selection flow, making it a 3-step process: Choose Blueprint → Blueprint details → Site name & details
• Reuse the existing deeplink confirmation screen (BlueprintDetails) for both deeplink and manual flows, with a dynamic source indicator (deeplink, file, or featured)
• Navigate directly from file upload on the grid to the Blueprint details step
• Consolidate blueprintDeeplinkWarnings and file blueprint warnings into a single shared blueprintWarnings state
• Rename BlueprintDeeplink component to BlueprintDetails to reflect its broader usage

CleanShot.2026-02-13.at.13.41.18.mp4

Testing Instructions

1. Open Studio and go to "Add Site"
2. Select "Start from a Blueprint" to see the blueprint grid
3. Click a featured blueprint and click "Continue" — verify the new Blueprint details step shows with "Featured Blueprint" in the footer
4. Click "Back" to return to the grid, then click "Continue" again — verify the details step still works
5. Upload a blueprint JSON file with warnings (you can use example blueprints from here: 3a658-pb) — verify it navigates to the Blueprint details step with "Blueprint loaded from file" in the footer and warnings displayed
6. Click "Back" to return to the grid, then click "Continue" — verify the file warnings are still shown
7. Select a different featured blueprint — verify any file warnings are cleared
8. Test the deeplink flow by opening a blueprint URL (you can use example blueprint deeplinks from here: https://jsbin.com/kulaqijega/1/edit?html,css,output) — verify the 2-step deeplink flow still works with "Blueprint loaded from URL" in the footer
9. Verify the stepper shows 3 steps for manual flow and 2 steps for deeplink flow
10. Creating a site with any blueprint selected should work well

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[bcotrim]

LGTM and works as described!

Could we clean up the blueprintWarnings from blueprints.tsx since we no longer use it?

[ivan-ottinger]

LGTM and works as described!

Could we clean up the blueprintWarnings from blueprints.tsx since we no longer use it?

Thanks for the review, Bernardo! Good catch! I've removed the unused
blueprintWarnings state and the BlueprintWarningNotice rendering from
blueprints.tsx in commit 6ab1ae4.

[wpmobilebot]

📊 Performance Test Results

Comparing 6ab1ae4 vs trunk

site-editor

Metric	trunk	6ab1ae4	Diff	Change
load	2712.00 ms	2712.00 ms	0.00 ms	⚪ 0.0%

site-startup

Metric	trunk	6ab1ae4	Diff	Change
siteCreation	7079.00 ms	6077.00 ms	-1002.00 ms	🟢 -14.2%
siteStartup	3928.00 ms	3931.00 ms	+3.00 ms	⚪ 0.0%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)

[bcotrim]

LGTM 👍