ci: replace insecure workflow with dotnet build

.github/workflows/main.yml

@@ -1,25 +1,50 @@
 name: CI
 
-on: [push, workflow_dispatch]
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+  workflow_dispatch:
 
 jobs:
   build:
-
-    runs-on: windows-latest
+    runs-on: ubuntu-latest
 
     steps:
-    - name: Download
-      run: Invoke-WebRequest https://bin.equinox.io/c/bNyj1mQVY4c/ngrok-v3-stable-windows-amd64.zip -OutFile ngrok.zip
-    - name: Extract
-      run: Expand-Archive ngrok.zip
-    - name: Auth
-      run: .\ngrok\ngrok.exe authtoken $Env:NGROK_AUTH_TOKEN
-      env:
-        NGROK_AUTH_TOKEN: ${{ secrets.NGROK_AUTH_TOKEN }}
-    - name: Enable TS
-      run: Set-ItemProperty -Path 'HKLM:\System\CurrentControlSet\Control\Terminal Server'-name "fDenyTSConnections" -Value 0
-    - run: Enable-NetFirewallRule -DisplayGroup "Remote Desktop"
-    - run: Set-ItemProperty -Path 'HKLM:\System\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp' -name "UserAuthentication" -Value 1
-    - run: Set-LocalUser -Name "runneradmin" -Password (ConvertTo-SecureString -AsPlainText "P@ssw0rd!" -Force)
-    - name: Create Tunnel
-      run: .\ngrok\ngrok.exe tcp 3389
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup .NET
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: '8.0.x'
+
+      - name: Detect projects
+        id: detect
+        run: |
+          PROJECTS=$(find . -name '*.csproj' -not -path './.git/*')
+          COUNT=$(printf '%s\n' "$PROJECTS" | grep -c . || true)
+          echo "count=$COUNT" >> "$GITHUB_OUTPUT"
+          if [ "$COUNT" -gt 0 ]; then
+            echo "Found projects:" >> "$GITHUB_STEP_SUMMARY"
+            printf '%s\n' "$PROJECTS" >> "$GITHUB_STEP_SUMMARY"
+          else
+            echo "No .csproj files found" >> "$GITHUB_STEP_SUMMARY"
+          fi
+
+      - name: Restore
+        if: steps.detect.outputs.count != '0'
+        run: dotnet restore
+
+      - name: Build
+        if: steps.detect.outputs.count != '0'
+        run: dotnet build --no-restore --configuration Release
+
+      - name: Test
+        if: steps.detect.outputs.count != '0'
+        run: dotnet test --no-build --configuration Release --logger trx --results-directory TestResults
+
+      - name: No projects to build
+        if: steps.detect.outputs.count == '0'
+        run: echo "No .csproj found; nothing to build."