phase-0: foundation, both apps boot end to end

Monorepo (pnpm workspaces) with two deployable apps and three pure packages.

apps/api (Hono on Node): Zod validated env that fails fast and names the problem,
Kysely factories for SQLite and Postgres chosen by DATABASE_URL scheme, portable
migrations covering the whole SPEC section 5 schema, Better Auth with the four
roles and seeded demo accounts, localized error envelope, /healthz and /readyz,
graceful SIGTERM drain. Dialect specific SQL is confined to the two factories.

apps/web (Next.js App Router): locale routed shell in es and en with a language
switcher, sign in screen, and a runtime /api proxy so the browser only ever sees
one origin and cookies stay first party.

packages/i18n ships both catalogs complete; es is generated from COPY.md and a
test re-derives it from the document on every run so it cannot drift.
packages/contracts holds the Zod schemas and the typed client the web app uses.

Verified: 43 vitest tests, 14 Playwright tests on mobile and desktop, typecheck
and lint clean, migrate and seed from a clean database, sign in through the proxy
with CSRF rejection of foreign origins.

Not verified here: docker compose. This user has no access to the docker socket.

RULES.md is absent from docs/, so packages/rules exports only RULES_VERSION and
no tax rule, check digit or deadline was invented. See DECISIONS.md.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

apps/api/Dockerfile

@@ -0,0 +1,40 @@
+# syntax=docker/dockerfile:1
+
+# Build stage: the whole workspace is needed because apps/api imports the packages/*
+# source directly and tsup bundles it in.
+FROM node:22-slim AS build
+ENV PNPM_HOME=/pnpm PATH=/pnpm:$PATH
+RUN corepack enable
+WORKDIR /repo
+
+COPY package.json pnpm-lock.yaml pnpm-workspace.yaml tsconfig.base.json ./
+COPY apps/api/package.json apps/api/
+COPY apps/web/package.json apps/web/
+COPY packages/contracts/package.json packages/contracts/
+COPY packages/i18n/package.json packages/i18n/
+COPY packages/rules/package.json packages/rules/
+RUN --mount=type=cache,id=pnpm,target=/pnpm/store pnpm install --frozen-lockfile
+
+COPY packages packages
+COPY apps/api apps/api
+COPY docs docs
+RUN pnpm --filter @impuestos/api build
+RUN pnpm --filter @impuestos/api deploy --prod --legacy /prod/api
+
+FROM node:22-slim AS runtime
+ENV NODE_ENV=production
+WORKDIR /app
+
+# Owns ./data, the SQLite file and the local storage driver's files.
+RUN mkdir -p /app/data && chown -R node:node /app
+
+COPY --from=build --chown=node:node /prod/api/node_modules ./node_modules
+COPY --from=build --chown=node:node /repo/apps/api/dist ./dist
+COPY --from=build --chown=node:node /repo/apps/api/package.json ./package.json
+
+USER node
+EXPOSE 4000
+
+# SIGTERM is handled in src/index.ts: fail readiness, drain, close the pool, exit 0.
+# No init shim, so node stays PID 1 and receives the signal directly.
+CMD ["node", "dist/index.js"]