Solution-Wide Default Theme — `Directory.Build.props` (v1.48.0)

Set a default diagram theme for the entire solution without touching individual [ResultFlow] attributes. Add to Directory.Build.props (or any .csproj):

<PropertyGroup>
  <ResultFlowDefaultTheme>Dark</ResultFlowDefaultTheme>
</PropertyGroup>

Priority chain:

[ResultFlow(Theme = Dark)]           ← method attribute — always wins
  ↑
<ResultFlowDefaultTheme>Dark</...>   ← Directory.Build.props / .csproj
  ↑
Light                                ← built-in default

Accepted values: Light (default), Dark (case-insensitive). Applies to both REslava.Result.Flow and REslava.ResultFlow.

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