Add guestbook with WebAuthn admin and SQLite

Introduce server-rendered guestbook and moderation portal.
Persist data in SQLite (better-sqlite3); add WebAuthn YubiKey
admin auth, rate-limiting, spam heuristics, and sanitization.
Switch Docker image to run Node/standalone Astro (remove nginx),
update docker-compose, Dockerfile, astro.config, and package.json.
Add .env.example, docs/guestbook.md, gitignore updates, layouts,
API routes, and supporting lib/components/pages for the feature.

Dockerfile

@@ -1,28 +1,44 @@
+# Stage 1: Build the Astro app
 FROM node:20-alpine AS builder
 
 WORKDIR /app
 
-# Copy package files
-COPY package*.json ./
+# Install build dependencies for native modules (e.g. better-sqlite3)
+RUN apk add --no-cache python3 make g++
 
-# Install dependencies
+COPY package*.json ./
 RUN npm ci
 
-# Copy source code
 COPY . .
-
-# Build the site
 RUN npm run build
 
-# Production stage
-FROM nginx:alpine
+# Stage 2: Install production dependencies only
+FROM node:20-alpine AS deps
 
-# Copy built files to nginx
-COPY --from=builder /app/dist /usr/share/nginx/html
+WORKDIR /app
 
-# Copy nginx config
-COPY nginx.conf /etc/nginx/conf.d/default.conf
+RUN apk add --no-cache python3 make g++
 
-EXPOSE 80
+COPY package*.json ./
+RUN npm ci --omit=dev
 
-CMD ["nginx", "-g", "daemon off;"]
+# Stage 3: Runtime image
+FROM node:20-alpine AS runtime
+
+WORKDIR /app
+
+# Data directory for SQLite database
+RUN mkdir -p /data
+
+COPY --from=builder /app/dist ./dist
+COPY --from=deps /app/node_modules ./node_modules
+COPY package*.json ./
+
+ENV NODE_ENV=production
+ENV HOST=0.0.0.0
+ENV PORT=3000
+ENV DB_PATH=/data/guestbook.db
+
+EXPOSE 3000
+
+CMD ["node", "dist/server/entry.mjs"]