feat: add CI, Docker, auth, typed API client, shiki code blocks, e2e tests

- CI: GitHub Actions (bun 1.3.14, lint/typecheck/test/build/format gates)
- Docker: multi-stage standalone build + .dockerignore (next.config output=standalone)
- Auth: better-auth server (memory adapter, drizzle-swap-ready) + react client
  + /api/auth/[...all] route handler
- API: /api/health + /api/openapi routes, openapi-typescript codegen to
  types/api.ts, typed openapi-fetch client (lib/api, lib/http)
- Shiki: server-side CodeBlock component (escaped HTML)
- E2E: playwright home + health specs on dedicated :3100 (chromium 1243
  installed from GCS after CDN timeout)
- Dev: allow 127.0.0.1/localhost dev origins (HMR for local tooling)

Dockerfile

@@ -0,0 +1,34 @@
+# syntax = docker/dockerfile:1
+
+FROM oven/bun:1.3.14 AS base
+WORKDIR /app
+
+# --- deps ---
+FROM base AS deps
+COPY package.json bun.lock ./
+RUN bun install --frozen-lockfile
+
+# --- builder ---
+FROM base AS builder
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+ENV NEXT_TELEMETRY_DISABLED=1
+RUN bun run build
+
+# --- runner ---
+FROM base AS runner
+ENV NODE_ENV=production
+ENV NEXT_TELEMETRY_DISABLED=1
+RUN addgroup --system --gid 1001 nodejs \
+  && adduser --system --uid 1001 nextjs
+
+COPY --from=builder /app/public ./public
+COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
+COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
+
+USER nextjs
+EXPOSE 3000
+ENV PORT=3000
+ENV HOSTNAME=0.0.0.0
+
+CMD ["node", "server.js"]