Add comprehensive test suite, fix minor issues, rename function and file names to match approved verbs (#708)

.github/CONTRIBUTING.md

@@ -58,6 +58,25 @@ You can launch the prerelease version of Win11Debloat by running this command:
    .\Win11Debloat.ps1
    ```
 
+### Running Automated Tests
+
+The automated test cases use Pester 5 and do not modify the registry or other
+system state. The optional bootstrap step installs Pester for your user account
+when needed. To run the complete suite:
+
+```powershell
+.\Scripts\Run-Tests.ps1 -Bootstrap
+```
+
+After the initial setup, run the suite with:
+
+```powershell
+.\Scripts\Run-Tests.ps1
+```
+
+GitHub Actions runs the same test command with Windows PowerShell 5.1 for pull
+requests and pushes to `master`.
+
 ## Implementation Guidelines
 
 ### Project Structure
@@ -72,7 +91,7 @@ Win11Debloat/
 │   ├── Get.ps1                  # Script used for the quick launch method to automatically download and run Win11debloat
 │   ├── AppRemoval/              # App package removal logic
 │   ├── CLI/                     # Command-line interface helpers
-│   ├── Features/                # Feature apply/undo logic (e.g. InvokeChanges.ps1, ReplaceStartMenu.ps1)
+│   ├── Features/                # Feature apply/undo logic (e.g. Invoke-Changes.ps1, Replace-StartMenu.ps1)
 │   ├── FileIO/                  # File input/output helpers
 │   ├── GUI/                     # GUI window definitions and logic
 │   ├── Helpers/                 # Shared helper functions
@@ -220,7 +239,7 @@ Windows Registry Editor Version 5.00
 
 #### 1b. Implement the Feature Logic
 
-If your feature requires more than just applying a registry file, add custom logic to the main script in the appropriate section. In most cases this will involve creating a new entry in the `Invoke-FeatureApply` function (in `Scripts/Features/InvokeChanges.ps1`) for your new feature. If your feature also requires custom undo logic (beyond a simple registry file import), add a corresponding entry to the `Invoke-FeatureUndo` function in the same file.
+If your feature requires more than just applying a registry file, add custom logic to the main script in the appropriate section. In most cases this will involve creating a new entry in the `Invoke-FeatureApply` function (in `Scripts/Features/Invoke-Changes.ps1`) for your new feature. If your feature also requires custom undo logic (beyond a simple registry file import), add a corresponding entry to the `Invoke-FeatureUndo` function in the same file.
 
 #### 2. Add Feature to Features.json
 

.github/workflows/tests.yml

@@ -0,0 +1,26 @@
+name: Tests
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  pester:
+    name: Pester (Windows PowerShell 5.1)
+    runs-on: windows-latest
+    timeout-minutes: 15
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+
+      - name: Run tests
+        shell: powershell
+        run: ./Scripts/Run-Tests.ps1 -Bootstrap