ci: Add GitHub workflows for test, build, and publish

Add comprehensive CI/CD workflows:

**Test Workflow (test.yml)**
- Runs on push/PR to main/develop
- Executes all 189 xUnit tests on Ubuntu runner
- Publishes test results and artifacts
- Fast and cost-effective validation

**Build Workflow (build.yml)**
- Builds for iOS and macOS Catalyst
- Runs on macOS-14 runners (Apple Silicon)
- Parallel builds for all platforms
- Uploads build artifacts (7-day retention)
- Overall build status reporting

**Publish Workflow (publish.yml)**
- Triggered by version tags (v*.*.*)
- Creates GitHub releases with changelogs
- Builds signed releases for distribution
- Uploads iOS and macOS .zip artifacts
- Supports pre-release detection (alpha/beta/rc)
- Manual workflow dispatch option

Features:
- .NET 8.0 with MAUI workload
- Parallel job execution for performance
- Artifact management and retention
- Test result reporting
- Release automation with version tracking
- Comprehensive documentation in workflows/README.md

Platforms supported:
- iOS 15.0+ (iossimulator-arm64)
- macOS 12.0+ Catalyst (maccatalyst-arm64)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/build.yml

@@ -0,0 +1,90 @@
+name: Build
+
+on:
+  push:
+    branches: [ main, develop ]
+  pull_request:
+    branches: [ main, develop ]
+  workflow_dispatch:
+
+jobs:
+  build-ios:
+    name: Build iOS
+    runs-on: macos-14
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Setup .NET
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: '8.0.x'
+
+    - name: Install MAUI workload
+      run: dotnet workload install maui --source https://api.nuget.org/v3/index.json
+
+    - name: Restore dependencies
+      run: dotnet restore HihaArvio.sln
+
+    - name: Build iOS
+      run: dotnet build src/HihaArvio/HihaArvio.csproj -f net8.0-ios -c Release /p:ArchiveOnBuild=false /p:EnableCodeSigning=false
+
+    - name: Upload iOS build artifacts
+      uses: actions/upload-artifact@v4
+      with:
+        name: ios-build
+        path: |
+          src/HihaArvio/bin/Release/net8.0-ios/**/*.app
+          src/HihaArvio/bin/Release/net8.0-ios/**/*.ipa
+        retention-days: 7
+
+  build-maccatalyst:
+    name: Build macOS Catalyst
+    runs-on: macos-14
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Setup .NET
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: '8.0.x'
+
+    - name: Install MAUI workload
+      run: dotnet workload install maui --source https://api.nuget.org/v3/index.json
+
+    - name: Restore dependencies
+      run: dotnet restore HihaArvio.sln
+
+    - name: Build macOS Catalyst
+      run: dotnet build src/HihaArvio/HihaArvio.csproj -f net8.0-maccatalyst -c Release /p:ArchiveOnBuild=false /p:EnableCodeSigning=false
+
+    - name: Upload macOS build artifacts
+      uses: actions/upload-artifact@v4
+      with:
+        name: maccatalyst-build
+        path: |
+          src/HihaArvio/bin/Release/net8.0-maccatalyst/**/*.app
+          src/HihaArvio/bin/Release/net8.0-maccatalyst/**/*.pkg
+        retention-days: 7
+
+  build-status:
+    name: Build Status
+    runs-on: ubuntu-latest
+    needs: [build-ios, build-maccatalyst]
+    if: always()
+
+    steps:
+    - name: Check build status
+      run: |
+        if [[ "${{ needs.build-ios.result }}" == "success" ]] && [[ "${{ needs.build-maccatalyst.result }}" == "success" ]]; then
+          echo "✅ All builds succeeded"
+          exit 0
+        else
+          echo "❌ One or more builds failed"
+          echo "iOS: ${{ needs.build-ios.result }}"
+          echo "macOS Catalyst: ${{ needs.build-maccatalyst.result }}"
+          exit 1
+        fi