Add Docker packaging and migrate from better-sqlite3 to libsql

Docker self-hosting support:
- Dockerfile (multi-stage Alpine build with tini init)
- docker-compose.yml with named volume for SQLite persistence
- /api/health endpoint for container health checks
- Auto-migration on startup via drizzle-orm/libsql/migrator
- Graceful shutdown (SIGTERM stops scheduler, closes DB)
- Next.js standalone output mode for minimal image size

Database driver migration (better-sqlite3 → @libsql/client):
- Eliminates native C++ compilation, enabling Alpine Docker images
- All DB queries converted from sync to async across services and routes
- DATABASE_URL now uses libsql file: prefix format
- drizzle.config.ts dialect changed to turso for libsql support
- Initial migration files generated in drizzle/

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Dockerfile

@@ -0,0 +1,41 @@
+FROM node:24-alpine AS base
+RUN corepack enable && corepack prepare pnpm@latest --activate
+
+# --- Dependencies ---
+FROM base AS deps
+WORKDIR /app
+COPY package.json pnpm-lock.yaml ./
+RUN pnpm install --frozen-lockfile
+
+# --- Builder ---
+FROM base AS builder
+WORKDIR /app
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+ENV NODE_ENV=production
+RUN pnpm build
+
+# --- Runner ---
+FROM node:24-alpine AS runner
+RUN apk add --no-cache tini
+WORKDIR /app
+
+ENV NODE_ENV=production
+ENV HOSTNAME=0.0.0.0
+ENV PORT=3000
+
+RUN addgroup --system --gid 1001 nodejs \
+    && adduser --system --uid 1001 nextjs \
+    && mkdir -p /data && chown nextjs:nodejs /data
+
+COPY --from=builder --chown=nextjs:nodejs /app/public ./public
+COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
+COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
+COPY --from=builder --chown=nextjs:nodejs /app/drizzle ./drizzle
+
+USER nextjs
+EXPOSE 3000
+VOLUME /data
+
+ENTRYPOINT ["/sbin/tini", "--"]
+CMD ["node", "server.js"]