chore: add gosec in CI

.github/workflows/backend-build.yml

@@ -12,7 +12,7 @@ on:
 
 jobs:
     lint:
-        name: Static Analysis (golangci-lint)
+        name: Static Analysis (golangci-lint + gosec)
         runs-on: ubuntu-latest
 
         steps:
@@ -24,6 +24,10 @@ jobs:
                   go-version: "1.24.4"
                   cache-dependency-path: backend/gestion/go.sum
 
+            - name: Download dependencies
+              working-directory: backend/gestion
+              run: go mod download
+
             - name: golangci-lint
               uses: golangci/golangci-lint-action@v6
               continue-on-error: true
@@ -32,6 +36,14 @@ jobs:
                   working-directory: backend/gestion
                   args: --timeout=5m
 
+            - name: Install gosec
+              run: go install github.com/securego/gosec/v2/cmd/gosec@latest
+
+            - name: Run Gosec Security Scanner
+              working-directory: backend/gestion
+              run: gosec ./...
+              continue-on-error: true
+
     build:
         name: Build
         needs: lint