fix(warnings): ASP0006

[eduardosmaniotto]

Summary

Eliminates all 33 ASP0006 warnings by replacing manual RenderTreeBuilder
sequence counters with Razor markup (compiler-generated sequence numbers).
Rendered output is unchanged.

• EnumSelect.cs → EnumSelect.razor + code-behind (same binder expression,
  splat-first attributes, conditional selected); plus bUnit coverage
• New EditShell wrapper (Breadcrumb, <h1>, CascadingValue) + one
  .razor file per edit page (EditAccount, EditConnectionServer,
  EditConfig); AutoForm<> renders via DynamicComponent with identical
  parameters and callbacks. EditBase data logic untouched
• Last 4 warnings suppressed with a documented #pragma at the single
  BaseComponentBuilder funnel: runtime-selected components can't use
  literals, and the threaded counter is unique and stable per render
  (reason in <remarks>)

Verification

• dotnet build: 0 ASP0006, 0 errors, no new warnings
• dotnet test MUnique.OpenMU.Web.Tests: 203/203 pass
• Manual smoke: open the three edit pages, change a value, save;
  check enum dropdowns render and select correctly