Redesign host row layout, fix Docker build, add S3 Singapore

- Host row: two-layer layout with name/URL on the left (normal flow)
  and latency/stats on the right (absolute positioned), preventing
  overlap and keeping sparklines aligned
- Docker: install git in build stage and include .git in context so
  vite can resolve commit hash for footer
- Add S3 ap-southeast-1 (Singapore) endpoint for AWS peering comparison

Dockerfile

@@ -3,6 +3,7 @@ FROM node@sha256:e4bf2a82ad0a4037d28035ae71529873c069b13eb0455466ae0bc13363826e3
 WORKDIR /app
 COPY package.json yarn.lock ./
 RUN yarn install --frozen-lockfile
+RUN apk add --no-cache git
 COPY . .
 RUN yarn build