feat: .git buildkit

bff/Dockerfile

@@ -1,3 +1,5 @@
+# syntax=docker/dockerfile:1
+
 FROM golang:1.26.5-alpine AS builder
 
 WORKDIR /src
@@ -11,10 +13,13 @@ COPY pkg ./pkg
 COPY bff/go.mod bff/go.sum ./bff/
 
 WORKDIR /src/bff
-RUN go mod download
+RUN --mount=type=cache,target=/go/pkg/mod \
+    go mod download
 
 COPY bff/ ./
-RUN go build -ldflags="-s -w" -o /out/bff .
+RUN --mount=type=cache,target=/go/pkg/mod \
+    --mount=type=cache,target=/root/.cache/go-build \
+    go build -ldflags="-s -w" -o /out/bff .
 
 FROM alpine:3.22