Update solution file references to .slnx in CI and docs

All dotnet commands and documentation now reference KZDev.PerfUtils.slnx instead of KZDev.PerfUtils.sln. This ensures consistency across CI workflows and README instructions following the solution file rename.

Author: kzdev-net

.github/workflows/ci.yml

@@ -21,13 +21,13 @@ jobs:
           dotnet-version: 10.x
 
       - name: Restore
-        run: dotnet restore Source/KZDev.PerfUtils.sln
+        run: dotnet restore Source/KZDev.PerfUtils.slnx
 
       - name: Build
-        run: dotnet build Source/KZDev.PerfUtils.sln -c Release
+        run: dotnet build Source/KZDev.PerfUtils.slnx -c Release
 
       - name: Test (standard)
-        run: dotnet test Source/KZDev.PerfUtils.sln -c Release --no-build
+        run: dotnet test Source/KZDev.PerfUtils.slnx -c Release --no-build
 
       - name: Upload Release artifacts
         uses: actions/upload-artifact@v4
@@ -75,6 +75,6 @@ jobs:
 
       - name: Test (Explicit only, sequential xUnit)
         run: |
-          dotnet test Source/KZDev.PerfUtils.sln -c Release --no-build \
+          dotnet test Source/KZDev.PerfUtils.slnx -c Release --no-build \
             --filter "TestMode=Explicit" \
             -- xUnit.Explicit=only xUnit.MaxParallelThreads=1 xUnit.ParallelizeAssembly=false xUnit.ParallelizeTestCollections=false

.github/workflows/docfx-publish.yml

@@ -30,7 +30,7 @@ jobs:
         with:
           dotnet-version: 10.x
 
-      - run: dotnet restore Source/KZDev.PerfUtils.sln
+      - run: dotnet restore Source/KZDev.PerfUtils.slnx
       - run: dotnet build -c Release Source/Src/KZDev.PerfUtils/KZDev.PerfUtils.csproj
       - run: dotnet tool update -g docfx
       - run: docfx Source/Docs/docfx.json

Source/Tst/README.md

@@ -2,7 +2,7 @@
 
 This document covers **local `dotnet test`** workflows (standard vs Explicit) and **Linux Docker** runs.
 
-Unless noted otherwise, run commands from the **`Source`** directory (the folder that contains `KZDev.PerfUtils.sln`). The solution uses **artifacts output** (`UseArtifactsOutput`); test build outputs live under **`artifacts/bin/<ProjectName>/release_net*`** at the repository root, not under each project’s `bin` folder.
+Unless noted otherwise, run commands from the **`Source`** directory (the folder that contains `KZDev.PerfUtils.slnx`). The solution uses **artifacts output** (`UseArtifactsOutput`); test build outputs live under **`artifacts/bin/<ProjectName>/release_net*`** at the repository root, not under each project’s `bin` folder.
 
 ---
 
@@ -13,17 +13,17 @@ Restores, builds, and runs **non-Explicit** tests with the defaults wired in `Di
 **PowerShell or cmd (from `Source`):**
 
 ```cmd
-dotnet restore KZDev.PerfUtils.sln
-dotnet build KZDev.PerfUtils.sln -c Release
-dotnet test KZDev.PerfUtils.sln -c Release --no-build
+dotnet restore KZDev.PerfUtils.slnx
+dotnet build KZDev.PerfUtils.slnx -c Release
+dotnet test KZDev.PerfUtils.slnx -c Release --no-build
 ```
 
 **bash (from `Source`):**
 
 ```bash
-dotnet restore KZDev.PerfUtils.sln
-dotnet build KZDev.PerfUtils.sln -c Release
-dotnet test KZDev.PerfUtils.sln -c Release --no-build
+dotnet restore KZDev.PerfUtils.slnx
+dotnet build KZDev.PerfUtils.slnx -c Release
+dotnet test KZDev.PerfUtils.slnx -c Release --no-build
 ```
 
 `[Fact(Explicit = true)]` tests are **skipped** in this default configuration.
@@ -39,13 +39,13 @@ This repository’s `dotnet test` path uses **VSTest** (not Microsoft Testing Pl
 **One-shot command (from `Source`, after a Release build):**
 
 ```cmd
-dotnet test KZDev.PerfUtils.sln -c Release --no-build --filter "TestMode=Explicit" -- xUnit.Explicit=only xUnit.MaxParallelThreads=1 xUnit.ParallelizeAssembly=false xUnit.ParallelizeTestCollections=false
+dotnet test KZDev.PerfUtils.slnx -c Release --no-build --filter "TestMode=Explicit" -- xUnit.Explicit=only xUnit.MaxParallelThreads=1 xUnit.ParallelizeAssembly=false xUnit.ParallelizeTestCollections=false
 ```
 
 **bash** (keep the filter expression in quotes so the shell does not treat `=` specially):
 
 ```bash
-dotnet test KZDev.PerfUtils.sln -c Release --no-build --filter "TestMode=Explicit" -- xUnit.Explicit=only xUnit.MaxParallelThreads=1 xUnit.ParallelizeAssembly=false xUnit.ParallelizeTestCollections=false
+dotnet test KZDev.PerfUtils.slnx -c Release --no-build --filter "TestMode=Explicit" -- xUnit.Explicit=only xUnit.MaxParallelThreads=1 xUnit.ParallelizeAssembly=false xUnit.ParallelizeTestCollections=false
 ```
 
 **Notes:**