v0.6.0 — Backup & Restore page; install netcat for Postgres-wait

Version the backup/restore feature that merged in unversioned, and add
netcat-openbsd to the bookworm-slim runtime so the new entrypoint Postgres
readiness check (nc -z postgres 5432) works instead of looping forever.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -26,7 +26,7 @@ RUN npm run build
 FROM node:20-bookworm-slim AS runtime
 WORKDIR /app
 RUN apt-get update && apt-get install -y --no-install-recommends \
-    openssl ca-certificates tini tzdata \
+    openssl ca-certificates tini tzdata netcat-openbsd \
   && rm -rf /var/lib/apt/lists/*
 ENV NODE_ENV=production
 ENV NEXT_TELEMETRY_DISABLED=1