docs(Unleash): add version.txt and README.md

Author: PSanetra

src/OpenFeature.Contrib.Providers.Unleash/README.md

@@ -0,0 +1,112 @@
+# Unleash .NET Provider
+
+The Unleash provider allows you to use [Unleash](https://www.getunleash.io/) with the OpenFeature .NET SDK.
+
+# .Net SDK usage
+
+## Requirements
+
+- open-feature/dotnet-sdk v2.x
+- Unleash .NET SDK v6.x
+
+## Install dependencies
+
+The first thing we will do is install the **OpenFeature SDK** and the **Unleash Feature Flag provider**.
+
+### .NET Cli
+
+```shell
+dotnet add package OpenFeature.Contrib.Providers.Unleash
+```
+
+### Package Manager
+
+```shell
+NuGet\Install-Package OpenFeature.Contrib.Providers.Unleash
+```
+
+### Package Reference
+
+```xml
+<PackageReference Include="OpenFeature.Contrib.Providers.Unleash" />
+```
+
+### Packet cli
+
+```shell
+paket add OpenFeature.Contrib.Providers.Unleash
+```
+
+### Cake
+
+```shell
+// Install OpenFeature.Contrib.Providers.Unleash as a Cake Addin
+#addin nuget:?package=OpenFeature.Contrib.Providers.Unleash
+
+// Install OpenFeature.Contrib.Providers.Unleash as a Cake Tool
+#tool nuget:?package=OpenFeature.Contrib.Providers.Unleash
+```
+
+## Using the Unleash Provider with the OpenFeature SDK
+
+```csharp
+using OpenFeature;
+using OpenFeature.Contrib.Providers.Unleash;
+using Unleash;
+
+var settings = new UnleashSettings
+{
+    AppName = "my-app",
+    UnleashApi = new Uri("http://localhost:4242/api/"),
+    CustomHttpHeaders = new Dictionary<string, string>
+    {
+        { "Authorization", "*:development.your-api-token" }
+    }
+};
+
+var provider = new UnleashProvider(settings);
+
+// Set the provider for the OpenFeature SDK
+await Api.Instance.SetProviderAsync(provider);
+
+// Get an OpenFeature client
+var client = Api.Instance.GetClient();
+
+// Boolean evaluation (uses IsEnabled)
+var enabled = await client.GetBooleanValueAsync("my-feature", false);
+
+// String evaluation (uses variant payload)
+var value = await client.GetStringValueAsync("my-variant-flag", "default");
+
+// Integer evaluation (parses variant payload)
+var count = await client.GetIntegerValueAsync("my-int-flag", 0);
+
+// Double evaluation (parses variant payload)
+var rate = await client.GetDoubleValueAsync("my-double-flag", 0.0);
+```
+
+## EvaluationContext and Unleash Context relationship
+
+The provider maps OpenFeature `EvaluationContext` fields to `UnleashContext`:
+
+| EvaluationContext Key | Unleash Context Field |
+|-----------------------|------------------------|
+| `TargetingKey`        | `UserId`               |
+| `sessionId`           | `SessionId`            |
+| `remoteAddress`       | `RemoteAddress`        |
+| `environment`         | `Environment`          |
+| `appName`             | `AppName`              |
+| `currentTime`         | `CurrentTime`          |
+| All other keys        | `Properties`           |
+
+## Variant payload type metadata
+
+When evaluating variants (string, integer, double, structure), the provider exposes the Unleash payload `type` field (e.g., `"string"`, `"number"`, `"json"`, `"csv"`) as `payload-type` in the resolution details flag metadata.
+
+## Events
+
+The provider emits `ProviderConfigurationChanged` events when Unleash fires `TogglesUpdatedEvent` (i.e., when toggle state is refreshed from the server).
+
+## Known issues and limitations
+
+- The provider does not accept an external `IUnleash` instance because lifecycle events (`ReadyEvent`, `ErrorEvent`, `TogglesUpdatedEvent`) can only be subscribed during client construction.

src/OpenFeature.Contrib.Providers.Unleash/version.txt

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+0.1.0