Add convert-blazor-server-to-webapp skill

[halter73]

Add a new skill to guide agents through converting pre-.NET 8 (and later) Blazor Server apps to the .NET 8+ Blazor Web App model. The skill covers:

• Replacing AddServerSideBlazor/MapBlazorHub with AddRazorComponents/MapRazorComponents
• Converting _Host.cshtml to an App.razor root component
• Creating Routes.razor from the old App.razor
• Replacing blazor.server.js with blazor.web.js
• Adding UseAntiforgery middleware
• Migrating CascadingAuthenticationState to a service
• Optional improvements like MapStaticAssets

Includes 4 eval scenarios: basic conversion, auth state migration, prerendering-disabled case, and a negative test for already-converted apps.

This was helpful when working on bartonjs/apireview.net#4

[Copilot]

Pull request overview

Adds a new .NET skill and accompanying eval coverage to help agents migrate pre-.NET 8 Blazor Server apps to the .NET 8+ Blazor Web App hosting model (AddRazorComponents/MapRazorComponents, App.razor root, Routes.razor, blazor.web.js, antiforgery, auth state migration).

Changes:

• Introduces the convert-blazor-server-to-webapp skill documentation with a step-by-step migration workflow and pitfalls.
• Adds 4 eval scenarios covering: basic conversion, CascadingAuthenticationState migration, prerendering-disabled preservation, and an “already converted” case.
• Updates CODEOWNERS to assign ownership for the new skill and tests (and fixes indentation on two existing entries).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 5 comments.

File	Description
tests/dotnet/convert-blazor-server-to-webapp/eval.yaml	Adds eval scenarios/assertions/rubrics for the new migration skill.
plugins/dotnet/skills/convert-blazor-server-to-webapp/SKILL.md	Adds the skill guidance for performing the Blazor Server → Blazor Web App conversion.
.github/CODEOWNERS	Adds owners for the new skill/test directories; normalizes two existing lines’ indentation.

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[ViktorHofer]

/evaluate

[github-actions]

Skill Validation Results

Skill	Scenario	Baseline	With Skill	Δ	Skills Loaded	Overfit	Verdict
convert-blazor-server-to-webapp	Basic Blazor Server app conversion to Blazor Web App	3.0/5	5.0/5	+2.0	✅ convert-blazor-server-to-webapp; tools: skill	✅ 0.04	✅
convert-blazor-server-to-webapp	Blazor Server app with CascadingAuthenticationState	3.0/5	5.0/5	+2.0	✅ convert-blazor-server-to-webapp; tools: skill, bash, create	✅ 0.04	✅
convert-blazor-server-to-webapp	Blazor Server app with prerendering disabled	5.0/5	5.0/5	0.0	✅ convert-blazor-server-to-webapp; tools: skill, bash	✅ 0.04	❌
convert-blazor-server-to-webapp	App already using Blazor Web App model — no migration needed	5.0/5	5.0/5	0.0	ℹ️ not activated (expected)	✅ 0.04	❌

Model: claude-opus-4.6 | Judge: claude-opus-4.6

Full results

[halter73]

/evaluate

[timheuer]

@halter73 We should move this OUT of dotnet plugin and establish dotnet-aspnet plugin structure and root this there. (see MAUI PR for example)

[ViktorHofer]

/evaluate

[mattleibow]

Should this be in a aspnetcore plugin set vs plain dotnet?

[ViktorHofer]

dotnet-aspnet plugin 👍

[halter73]

I moved it into a new dotnet-aspnet plugin directory similar to #199. Should we call it dotnet-aspnetcore? ducks (I prefer the current dotnet-aspnet naming to be clear)

[ManishJayaswal]

@adityamandaleeka @BrennanConroy - please review

[danmoseley]

#357 creates a dotnet-blazor plugin. If there's going to be a blazor plugin presumably this should go in there. if not #357 should go in this dotnet-aspnet plugin.

[javiercn]

I think it would be best if we combine this with #357

[halter73]

@javiercn I'm going to close this with the idea that the content should be moved to #357 assuming we want to keep it. Let me know if you want any help with this.