Update docs and bump OpenApi, SwaggerUI, TinyHelpers

[marcominerva]

Clarified ConfigureAwait usage in copilot-instructions.md and removed Azure-specific rules. Updated package references in MinimalSample.csproj and MinimalHelpers.OpenApi.csproj to latest versions for Microsoft.AspNetCore.OpenApi, Swashbuckle.AspNetCore.SwaggerUI, and TinyHelpers.AspNetCore.

[Copilot]

Pull request overview

Updates contributor guidance and refreshes a few NuGet dependencies used by the OpenApi helper library and the minimal sample.

Changes:

• Clarifies when ConfigureAwait(false) should be used (library code with potential SynchronizationContext consumers) and removes Azure-specific guidance from .github/copilot-instructions.md.
• Bumps Microsoft.AspNetCore.OpenApi versions across target frameworks in MinimalHelpers.OpenApi.
• Updates sample package references for Microsoft.AspNetCore.OpenApi, Swashbuckle.AspNetCore.SwaggerUI, and TinyHelpers.AspNetCore.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/MinimalHelpers.OpenApi/MinimalHelpers.OpenApi.csproj	Updates Microsoft.AspNetCore.OpenApi package versions for net8.0, net9.0, and net10.0.
samples/MinimalSample/MinimalSample.csproj	Updates OpenApi/SwaggerUI/TinyHelpers package references for the sample app.
.github/copilot-instructions.md	Refines async guidance around ConfigureAwait(false) and removes Azure-specific rules.