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/web/package.json

@@ -0,0 +1,35 @@
+{
+  "name": "@impuestos/web",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "next dev --port 3000",
+    "build": "next build",
+    "start": "next start --port 3000",
+    "typecheck": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@impuestos/contracts": "workspace:*",
+    "@impuestos/i18n": "workspace:*",
+    "@tanstack/react-query": "^5.102.8",
+    "better-auth": "^1.7.2",
+    "class-variance-authority": "^0.7.1",
+    "clsx": "^2.1.1",
+    "lucide-react": "^1.40.0",
+    "next": "^16.3.4",
+    "next-intl": "^4.14.2",
+    "react": "^19.2.8",
+    "react-dom": "^19.2.8",
+    "tailwind-merge": "^3.6.0",
+    "zod": "^4.5.4"
+  },
+  "devDependencies": {
+    "@tailwindcss/postcss": "^4.3.3",
+    "@types/node": "^26.4.1",
+    "@types/react": "^19.2.18",
+    "@types/react-dom": "^19.2.7",
+    "tailwindcss": "^4.3.3",
+    "typescript": "^5.9.3"
+  }
+}