feat: print git commit during startup

server/Dockerfile

@@ -1,10 +1,11 @@
 FROM golang:1.24.7 AS build
+ARG GIT_COMMIT=unknown
 WORKDIR /src
 COPY . .
 RUN --mount=type=cache,target=/go/pkg/mod \
     --mount=type=cache,target=/root/.cache/go-build \
     CGO_ENABLED=0 GOOS=linux GOARCH=amd64 \
-    go build -trimpath -ldflags="-s -w" \
+    go build -trimpath -ldflags="-s -w -X main.commit=${GIT_COMMIT}" \
     -o /out/server ./server/cmd/marka-server
 
 FROM scratch