feat: Pass build metadata args in Gitea CI pipeline

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitea/workflows/build.yaml

@@ -31,5 +31,9 @@ jobs:
             TAG=${{ inputs.tag }}
           fi
           IMAGE=gitea.home.hrajfrisbee.cz/${{ github.repository }}:$TAG
-          docker build -f build/Dockerfile -t $IMAGE .
+          docker build -f build/Dockerfile \
+            --build-arg GIT_TAG=$TAG \
+            --build-arg GIT_COMMIT=${{ github.sha }} \
+            --build-arg BUILD_DATE=$(date -u +%Y-%m-%dT%H:%M:%SZ) \
+            -t $IMAGE .
           docker push $IMAGE