fix wrong parametre working dir and add cache dependency

.github/workflows/build.yml

@@ -41,6 +41,7 @@ jobs:
         uses: actions/setup-go@v5
         with:
           go-version: '1.24.0'
+          cache-dependency-path: backend/go.sum
 
       - name: Set up Git credentials for private modules
         run: |
@@ -48,16 +49,6 @@ jobs:
         env:
           GH_PAT_FOR_MODULES: ${{ secrets.GH_PAT }}
 
-      - name: Restore Go module cache
-        uses: actions/cache@v4
-        with:
-          path: |
-            ~/go/pkg/mod
-            ~/.cache/go-build # Optional, but good for build cache
-          key: ${{ runner.os }}-${{ matrix.goos }}-${{ matrix.goarch }}-go-${{ hashFiles('backend/go.sum') }}
-          restore-keys: |
-            ${{ runner.os }}-${{ matrix.goos }}-${{ matrix.goarch }}-go-
-
       - name: Go Mod Tidy & Download
         working-directory: ./backend
         run: go mod tidy -v
@@ -65,11 +56,10 @@ jobs:
       - name: Build go backend binary
         working-directory: ./backend
         run: |
-          mkdir -p build
           if [ "${{ matrix.goos }}" == "windows" ]; then
-            GOOS=${{ matrix.goos }} GOARCH=${{ matrix.goarch }} go build -o build/server-${{ matrix.goos }}-${{ matrix.goarch }}.exe main.go
+            GOOS=${{ matrix.goos }} GOARCH=${{ matrix.goarch }} go build -o ../server-${{ matrix.goos }}-${{ matrix.goarch }}.exe main.go
           else
-            GOOS=${{ matrix.goos }} GOARCH=${{ matrix.goarch }} go build -o build/server-${{ matrix.goos }}-${{ matrix.goarch }} main.go
+            GOOS=${{ matrix.goos }} GOARCH=${{ matrix.goarch }} go build -o ../server-${{ matrix.goos }}-${{ matrix.goarch }} main.go
           fi
 
       - name: Upload build artifacts
@@ -78,4 +68,4 @@ jobs:
           name: lightcontroller-${{ matrix.goos }}-${{ matrix.goarch }}
           path: |
             ./dist/spa
-            ./backend/build/
+            server-${{ matrix.goos }}-${{ matrix.goarch }}${{ (matrix.goos == 'windows' && '.exe') || '' }}