feat: Update to latest CS2/CSS API and .NET 8.0

- Update TargetFramework from net7.0 to net8.0
- Update CounterStrikeSharp.API from 1.0.126 to 1.0.363
- Update MinimumApiVersion from 126 to 363
- Bump ModuleVersion to 0.0.6
- FIX: Replace deprecated EyeAngles with V_angle (fixes #5)
- FIX: Fix closure capture bug in timer callbacks (race condition)
- Add null checks for player pawn data
- Add xUnit test project with core logic tests
- Update solution file to include test project
- Update README with development instructions and changelog

Workflow update will be handled separately due to GitHub token scope requirements.

This update ensures compatibility with the latest Counter-Strike 2
and CounterStrikeSharp API versions.

Flashlight.Tests/Flashlight.Tests.csproj

@@ -0,0 +1,29 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net8.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+        <IsPackable>false</IsPackable>
+        <IsTestProject>true</IsTestProject>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+        <PackageReference Include="xunit" Version="2.6.2" />
+        <PackageReference Include="xunit.runner.visualstudio" Version="2.5.4">
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+            <PrivateAssets>all</PrivateAssets>
+        </PackageReference>
+        <PackageReference Include="coverlet.collector" Version="6.0.0">
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+            <PrivateAssets>all</PrivateAssets>
+        </PackageReference>
+        <PackageReference Include="Moq" Version="4.20.69" />
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="../Flashlight/Flashlight.csproj" />
+    </ItemGroup>
+
+</Project>