fix: move inline comments above FROM lines (fixes docker build)

Docker does not support inline comments on FROM lines. Move the
human-readable image tag comments to their own line above each FROM.

Fixes broken docker build on PR #126 and main.

Dockerfile

@@ -1,5 +1,6 @@
 # Build stage
-FROM golang@sha256:f6751d823c26342f9506c03797d2527668d095b0a15f1862cddb4d927a7a4ced AS builder # golang:1.25-alpine
+# golang:1.25-alpine
+FROM golang@sha256:f6751d823c26342f9506c03797d2527668d095b0a15f1862cddb4d927a7a4ced AS builder
 
 RUN apk add --no-cache git make gcc musl-dev
 
@@ -20,7 +21,8 @@ RUN make check
 RUN make build
 
 # Runtime stage
-FROM alpine@sha256:6baf43584bcb78f2e5847d1de515f23499913ac9f12bdf834811a3145eb11ca1 # alpine:3.19
+# alpine:3.19
+FROM alpine@sha256:6baf43584bcb78f2e5847d1de515f23499913ac9f12bdf834811a3145eb11ca1
 
 RUN apk add --no-cache ca-certificates tzdata git openssh-client docker-cli