Fix TFMs, exception args, stray semicolons, XML doc, and AGENTS.md from review feedback

AGENTS.md

@@ -8,23 +8,23 @@
 
 ## Build and test workflows
 - Solution: `FixedMathSharp.sln` with library project and test project.
-- Target frameworks are multi-targeted in both projects: `net48;net8`.
+- Target frameworks are configured in the respective `.csproj` files; `net8.0` is the primary TFM.
 - Typical local workflow:
   - `dotnet restore`
   - `dotnet build --configuration Debug --no-restore`
   - `dotnet test --configuration Debug`
 - CI detail from `.github/workflows/dotnet.yml`:
-  - Linux runs `net48` tests via Mono + `xunit.console.exe` and `net8` via `dotnet test -f net8`.
-  - Windows runs `dotnet test` for both TFMs.
+  - Linux and Windows both run `dotnet test` against the supported TFMs (with `net8.0` as the primary test target).
+  - Refer to the workflow file for the exact matrix of OS/TFM combinations.
 - Packaging/versioning comes from `src/FixedMathSharp/FixedMathSharp.csproj`: GitVersion variables are consumed when present, otherwise version falls back to `0.0.0`.
 
 ## Code conventions specific to this repo
 - Prefer `Fixed64` constants (`Fixed64.Zero`, `Fixed64.One`, `FixedMath.PI`) over primitive literals in math-heavy code.
 - Preserve saturating/guarded semantics in operators and math helpers (for example `Fixed64` add/sub overflow behavior).
 - When touching bounds logic, maintain cross-type dispatch shape in `Intersects(IBound)` and shared clamping projection via `IBoundExtensions.ProjectPointWithinBounds`.
-- Serialization compatibility is intentional:
-  - MessagePack attributes on serializable structs (`[MessagePackObject]`, `[Key]`) across TFMs.
-  - Conditional serializers in tests (`BinaryFormatter` for `NET48`, `System.Text.Json` for `NET8`).
+- Serialization compatibility is intentional and now uses MemoryPack:
+  - MemoryPack attributes on serializable structs (for example `[MemoryPackable]`, `[MemoryPackInclude]`) are the source of truth for serialized layouts.
+  - Tests use MemoryPack-based roundtrips (and `System.Text.Json` where appropriate) instead of legacy `MessagePack`/`BinaryFormatter` serializers.
 - `ThreadLocalRandom` is marked `[Obsolete]`; new deterministic RNG work should prefer `DeterministicRandom` and `DeterministicRandom.FromWorldFeature(...)` in `src/FixedMathSharp/Utility/DeterministicRandom.cs`.
 
 ## Testing patterns to mirror

src/FixedMathSharp/Bounds/BoundingArea.cs

@@ -209,7 +209,6 @@ public bool Intersects(IBound other)
 
                 default: return false; // Default case for unknown or unsupported types
             }
-            ;
         }
 
         /// <summary>

src/FixedMathSharp/Bounds/BoundingBox.cs

@@ -39,7 +39,7 @@ public partial struct BoundingBox : IBound, IEquatable<BoundingBox>
         public Vector3d Max { get; private set; }
 
         /// <summary>
-        /// 
+        /// Serialization/compatibility version of this <see cref="BoundingBox"/> instance.
         /// </summary>
         [MemoryPackOrder(2)]
         public byte Version { get; private set; }
@@ -238,7 +238,6 @@ public bool Intersects(IBound other)
                 default:
                     return false; // Default case for unknown or unsupported types
             }
-            ;
         }
 
         /// <summary>

src/FixedMathSharp/Bounds/BoundingSphere.cs

@@ -108,7 +108,6 @@ public bool Intersects(IBound other)
 
                 default: return false; // Default case for unknown or unsupported types
             }
-            ;
         }
 
         /// <summary>

src/FixedMathSharp/FixedMathSharp.csproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <!-- Define the target framework and compatibility -->
     <LangVersion>11.0</LangVersion>
-    <TargetFrameworks>netstandard2.1;net8</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;net8.0</TargetFrameworks>
     <!-- Versioning and Build Configuration -->
     <!-- Set SemVer to GitVersion_FullSemVer if available, otherwise fallback to 0.0.0 -->
     <SemVer Condition="'$(GitVersion_FullSemVer)' != ''">$(GitVersion_FullSemVer)</SemVer>
@@ -68,10 +68,6 @@
   <!-- Dependencies and Package References -->
   <ItemGroup>
 	<PackageReference Include="MemoryPack" Version="1.21.4" />
-	<PackageReference Condition="'$(TargetFrameworkIdentifier)' == '.NETFramework'" Include="Microsoft.NETFramework.ReferenceAssemblies.net48" Version="1.0.3">
-      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
-      <PrivateAssets>all</PrivateAssets>
-    </PackageReference>
   </ItemGroup>
   <!-- Ensure LICENSE, README, & icon files are included in the NuGet package -->
   <ItemGroup>

src/FixedMathSharp/Numerics/FixedQuaternion.cs

@@ -372,7 +372,7 @@ public static FixedQuaternion FromAxisAngle(Vector3d axis, Fixed64 angle)
 
             // Check if the angle is in a valid range (-pi, pi)
             if (angle < -FixedMath.PI || angle > FixedMath.PI)
-                throw new ArgumentOutOfRangeException($"Angle must be in the range ({-FixedMath.PI}, {FixedMath.PI}), but was {angle}");
+                throw new ArgumentOutOfRangeException(nameof(angle), angle, $"Angle must be in the range ({-FixedMath.PI}, {FixedMath.PI}), but was {angle}");
 
             Fixed64 halfAngle = angle / Fixed64.Two;  // Half-angle formula
             Fixed64 sinHalfAngle = FixedMath.Sin(halfAngle);
@@ -412,7 +412,7 @@ public static FixedQuaternion FromEulerAngles(Fixed64 pitch, Fixed64 yaw, Fixed6
                 yaw < -FixedMath.PI || yaw > FixedMath.PI ||
                 roll < -FixedMath.PI || roll > FixedMath.PI)
             {
-                throw new ArgumentOutOfRangeException($"Euler angles must be in the range ({-FixedMath.PI}, {FixedMath.PI}), but were ({pitch}, {yaw}, {roll})");
+                throw new ArgumentOutOfRangeException(nameof(pitch), $"Euler angles must be in the range ({-FixedMath.PI}, {FixedMath.PI}), but were ({pitch}, {yaw}, {roll})");
             }
 
             Fixed64 c1 = FixedMath.Cos(yaw / Fixed64.Two);

tests/FixedMathSharp.Tests/FixedMathSharp.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <LangVersion>11.0</LangVersion>
-    <TargetFrameworks>net8</TargetFrameworks>
+    <TargetFrameworks>net8.0</TargetFrameworks>
     <ImplicitUsings>disable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <IsPackable>false</IsPackable>
@@ -16,10 +16,6 @@
 	  <PrivateAssets>all</PrivateAssets>
 	</ProjectReference>
     <PackageReference Include="MemoryPack" Version="1.21.4" />
-	<PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies.net48" Version="1.0.3">
-	  <PrivateAssets>all</PrivateAssets>
-	  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
-	</PackageReference>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.3.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>