Fix Docker build for harness workspace dependency on @homelab/db

Switch harness Dockerfile to pnpm with repo root build context so
workspace:^ dependency on @homelab/db resolves. Use .dockercontext
marker file to opt individual apps into root context builds while
keeping web/api on their local app context.

.gitea/workflows/deploy-production.yaml

@@ -46,10 +46,16 @@ jobs:
           echo "${{ secrets.REGISTRY_TOKEN }}" | docker login gitea.coreworlds.io -u lazorgurl --password-stdin
           IFS=',' read -ra APPS <<< "${{ steps.changes.outputs.apps }}"
           for app in "${APPS[@]}"; do
+            if [ -f "apps/${app}/.dockercontext" ]; then
+              CONTEXT="."
+            else
+              CONTEXT="apps/${app}"
+            fi
             docker build \
               -t gitea.coreworlds.io/lazorgurl/homelab-${app}:${{ gitea.sha }} \
               -t gitea.coreworlds.io/lazorgurl/homelab-${app}:latest \
-              apps/${app}
+              -f apps/${app}/Dockerfile \
+              $CONTEXT
             docker push gitea.coreworlds.io/lazorgurl/homelab-${app}:${{ gitea.sha }}
             docker push gitea.coreworlds.io/lazorgurl/homelab-${app}:latest
           done