ci: fix build workflows - remove defaults.run.working-directory

All 4 build jobs failed because defaults.run.working-directory
chdir'd into subdirs before checkout created them.

- Remove defaults.run.working-directory from all reusable workflows
- Add per-step working-directory to run steps that need it
- Auth config step runs from repo root (no working-directory)

.gitea/workflows/build_server_core.yaml

@@ -6,12 +6,10 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
-    defaults:
-      run:
-        working-directory: apps/server-core
     steps:
       - name: Configure git auth for submodules
         run: git config --global url."https://x-access-token:${{ secrets.BUILD_TOKEN }}@git.datadunia.com/".insteadOf "https://git.datadunia.com/"
+
       - uses: actions/checkout@v4
         with:
           submodules: true
@@ -24,14 +22,17 @@ jobs:
           go-version: '1.26'
 
       - name: Download Go modules
+        working-directory: apps/server-core
         run: go mod download
 
       - name: Generate Swagger docs
+        working-directory: apps/server-core
         run: |
           go install github.com/swaggo/swag/cmd/swag@v1.16.6
           swag init -g main.go --parseDependency --parseInternal
 
       - name: Build
+        working-directory: apps/server-core
         run: go build -o bin/server-core .
 
       - name: Upload artifact