feat(backend): add standalone data plane

Replace the Supabase application data plane with the Node/PostgreSQL API, migrate mobile, admin, web, and MCP callers, add controlled cutover tooling, and define hardened Dokploy infrastructure.

apps/api/package.json

@@ -0,0 +1,43 @@
+{
+  "name": "@sauci/api",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "engines": {
+    "node": ">=20 <21"
+  },
+  "scripts": {
+    "dev": "tsx watch src/index.ts",
+    "dev:worker": "tsx watch src/workers/index.ts",
+    "build": "tsup src/index.ts src/db/migrate.ts src/migration/run.ts src/workers/index.ts --format esm --clean",
+    "start": "node dist/index.js",
+    "start:worker": "node dist/workers/index.js",
+    "db:generate": "drizzle-kit generate",
+    "db:migrate": "tsx src/db/migrate.ts",
+    "db:migrate:prod": "node dist/db/migrate.js",
+    "db:seed": "tsx src/db/seed.ts",
+    "migration:cutover": "tsx src/migration/run.ts",
+    "test": "vitest run",
+    "test:integration": "vitest run --config vitest.integration.config.ts",
+    "typecheck": "tsc --noEmit",
+    "lint": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@hono/node-server": "^1.13.7",
+    "@sauci/shared": "*",
+    "drizzle-orm": "^0.45.2",
+    "hono": "^4.6.0",
+    "jose": "^6.1.3",
+    "pg": "^8.17.2",
+    "zod": "^3.23.0"
+  },
+  "devDependencies": {
+    "@types/node": "^22.0.0",
+    "@types/pg": "^8.15.5",
+    "drizzle-kit": "^0.31.4",
+    "tsup": "^8.2.4",
+    "tsx": "^4.19.0",
+    "typescript": "^5.5.0",
+    "vitest": "^2.1.0"
+  }
+}