Migrate to .NET 10 and modernize build infrastructure (#14)

* Migrate to .NET 10 and modernize build infrastructure

- Migrate all projects to .NET 10 (Hjson, CLI, sample, and tests)
- Replace legacy .sln files with modern .slnx format
- Update project file structure for net10 target framework
- Remove legacy build system (Travis CI, build-mono script)
- Add GitHub Actions CI/CD workflows (ci.yml, format.yml, release.yml)
- Add developer container configuration (.devcontainer)
- Add EditorConfig and VS Code workspace settings
- Major refactoring of core library (HjsonReader, JsonWriter, etc.)
- Add new converter API (HjsonConvert, HjsonAttributes)
- Rewrite test suite with proper unit tests (HjsonConvertTests, ParserTests)
- Simplify CLI and sample applications
- Performance tunning
- dotnet format

Fixes #7
Fixes #10
Fixes #13

Author: cryi

.devcontainer/devcontainer.json

@@ -0,0 +1,18 @@
+{
+	"name": "C# (.NET 10)",
+	"image": "mcr.microsoft.com/dotnet/sdk:10.0",
+	"updateRemoteUserUID": true,
+	"workspaceMount": "source=${localWorkspaceFolder},target=/workspaces/${localWorkspaceFolderBasename},type=bind,Z",
+	"runArgs": [
+		"--userns=keep-id"
+	],
+	"customizations": {
+		"vscode": {
+			"extensions": [
+				"ms-dotnettools.csharp",
+				"ms-dotnettools.vscode-dotnet-runtime",
+				// "ms-dotnettools.csdevkit"
+			]
+		}
+	}
+}

.editorconfig

@@ -0,0 +1,28 @@
+name: CI
+
+on:
+  push:
+    branches: [ master, main ]
+  pull_request:
+    branches: [ master, main ]
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+    
+    steps:
+    - uses: actions/checkout@v4
+    
+    - name: Setup .NET
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: '10.0.x' # Uses latest stable .NET
+        
+    - name: Restore dependencies
+      run: dotnet restore
+      
+    - name: Build
+      run: dotnet build --configuration Release --no-restore
+      
+    - name: Test
+      run: dotnet test test/test.csproj --configuration Release --no-build --verbosity normal

.github/workflows/ci.yml

@@ -0,0 +1,22 @@
+name: Format Check
+
+on:
+  push:
+    branches: [ master, main ]
+  pull_request:
+    branches: [ master, main ]
+
+jobs:
+  format:
+    runs-on: ubuntu-latest
+    
+    steps:
+    - uses: actions/checkout@v4
+    
+    - name: Setup .NET
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: '10.0.x'
+        
+    - name: Format Check
+      run: dotnet format --verify-no-changes

.github/workflows/format.yml

@@ -0,0 +1,31 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*' # Trigger on tags like v4.0.0 or v4.0.0-rc.1
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Setup .NET
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: '10.0.x'
+
+    - name: Extract version from tag
+      id: version
+      run: echo "VERSION=${GITHUB_REF_NAME#v}" >> "$GITHUB_OUTPUT"
+
+    - name: Restore dependencies
+      run: dotnet restore Hjson/Hjson.csproj
+
+    - name: Pack Hjson
+      run: dotnet pack Hjson/Hjson.csproj --configuration Release --no-restore -o ./artifacts /p:Version=${{ steps.version.outputs.VERSION }}
+
+    - name: Push to NuGet
+      run: dotnet nuget push ./artifacts/*.nupkg --api-key ${{ secrets.NUGET_API_KEY }} --source https://api.nuget.org/v3/index.json --skip-duplicate

.github/workflows/release.yml

@@ -0,0 +1,10 @@
+{
+    "[csharp]": {
+        "editor.defaultFormatter": "ms-dotnettools.csharp",
+        "editor.formatOnSave": true,
+        "editor.formatOnType": true,
+        "editor.codeActionsOnSave": {
+            "source.fixAll.csharp": "explicit"
+        }
+    }
+}

.travis.yml

@@ -0,0 +1,5 @@
+<Solution>
+  <Project Path="Hjson/Hjson.csproj" />
+  <Project Path="cli/cli.csproj" />
+  <Project Path="test/test.csproj" Type="8bb2217d-0f2d-49d1-97bc-3654ed321f3b" />
+</Solution>