CUB-119: Fix CI workflow — replace .NET with Go backend build

.gitea/workflows/dev.yml

@@ -13,22 +13,18 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Setup .NET
-        uses: actions/setup-dotnet@v4
+      - name: Setup Go
+        uses: actions/setup-go@v5
         with:
-          dotnet-version: '9.0.x'
+          go-version: '1.23'
 
-      - name: Restore backend
-        run: dotnet restore
-        working-directory: ./backend
+      - name: Build go-backend
+        run: go build ./cmd/...
+        working-directory: ./go-backend
 
-      - name: Build backend
-        run: dotnet build --no-restore --configuration Release
-        working-directory: ./backend
-
-      - name: Test backend
-        run: dotnet test --no-build --configuration Release
-        working-directory: ./backend
+      - name: Test go-backend
+        run: go test ./...
+        working-directory: ./go-backend
 
       - name: Setup Node
         uses: actions/setup-node@v4