feat: add reusable .NET build & test workflow

Co-Authored-By: Claude Opus 5.5 <[email protected]>

.gitea/workflows/dotnet-build-test.yaml

@@ -0,0 +1,79 @@
+name: .NET Build & Test (Reusable)
+
+on:
+  workflow_call:
+    inputs:
+      solution:
+        description: "Solution/project file to build (relative to working-directory). Empty = let dotnet pick the single sln/proj in working-directory"
+        required: false
+        default: ""
+        type: string
+      dotnet-version:
+        description: ".NET SDK version"
+        required: false
+        default: "10.0.x"
+        type: string
+      configuration:
+        description: "Build configuration"
+        required: false
+        default: "Release"
+        type: string
+      warnaserror:
+        description: "Treat build warnings as errors"
+        required: false
+        default: true
+        type: boolean
+      working-directory:
+        description: "Path where dotnet commands are executed (relative to repo root)"
+        required: false
+        default: "."
+        type: string
+      test-filter:
+        description: "Optional dotnet test --filter expression"
+        required: false
+        default: ""
+        type: string
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+    env:
+      DOTNET_CLI_TELEMETRY_OPTOUT: "1"
+      DOTNET_NOLOGO: "1"
+      SOLUTION: ${{ inputs.solution }}
+      CONFIGURATION: ${{ inputs.configuration }}
+      WARNASERROR: ${{ inputs.warnaserror }}
+      TEST_FILTER: ${{ inputs.test-filter }}
+
+    defaults:
+      run:
+        shell: bash
+        working-directory: ${{ inputs.working-directory }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      - name: Setup .NET
+        uses: actions/setup-dotnet@v5
+        with:
+          dotnet-version: ${{ inputs.dotnet-version }}
+
+      - name: Restore
+        run: dotnet restore ${SOLUTION:+"$SOLUTION"}
+
+      - name: Build
+        run: |
+          ARGS=(-c "$CONFIGURATION" --no-restore)
+          if [ "$WARNASERROR" = "true" ]; then
+            ARGS+=(-warnaserror)
+          fi
+          dotnet build ${SOLUTION:+"$SOLUTION"} "${ARGS[@]}"
+
+      - name: Test
+        run: |
+          ARGS=(-c "$CONFIGURATION" --no-build)
+          if [ -n "$TEST_FILTER" ]; then
+            ARGS+=(--filter "$TEST_FILTER")
+          fi
+          dotnet test ${SOLUTION:+"$SOLUTION"} "${ARGS[@]}"