feat(db): implement complete database schema and models

- Add Prisma schema with PostgreSQL 15 support
- Create Users, Batches, Images, Payments, ApiKeys tables
- Implement proper foreign key relationships and indexes
- Add enum types for status fields (Plan, BatchStatus, ImageStatus, PaymentStatus)
- Support for JSON fields (vision_tags, metadata)
- UUID primary keys for security
- Created/updated timestamps with proper defaults

Database Layer Components:
- Prisma service with connection management and health checks
- Repository pattern for all entities with comprehensive CRUD operations
- TypeScript DTOs with class-validator decorations
- Swagger API documentation annotations
- Helper functions for business logic (quota management, pricing, etc.)

Development Support:
- Environment variables template
- Database seed script with realistic test data
- TypeScript configuration optimized for Nest.js
- Package.json with all required dependencies

Resolves database requirements from issues §78-81 establishing
the complete data layer foundation for the AI Bulk Image Renamer SaaS.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

packages/api/package.json

@@ -0,0 +1,98 @@
+{
+  "name": "@seo-image-renamer/api",
+  "version": "1.0.0",
+  "description": "AI Bulk Image Renamer SaaS - API Server",
+  "author": "Vibecode Together",
+  "private": true,
+  "license": "UNLICENSED",
+  "scripts": {
+    "build": "nest build",
+    "format": "prettier --write \"src/**/*.ts\" \"test/**/*.ts\"",
+    "start": "nest start",
+    "start:dev": "nest start --watch",
+    "start:debug": "nest start --debug --watch",
+    "start:prod": "node dist/main",
+    "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
+    "test": "jest",
+    "test:watch": "jest --watch",
+    "test:cov": "jest --coverage",
+    "test:debug": "node --inspect-brk -r tsconfig-paths/register -r ts-node/register node_modules/.bin/jest --runInBand",
+    "test:e2e": "jest --config ./test/jest-e2e.json",
+    "prisma:generate": "prisma generate",
+    "prisma:migrate": "prisma migrate dev",
+    "prisma:studio": "prisma studio",
+    "prisma:seed": "ts-node prisma/seed.ts",
+    "db:reset": "prisma migrate reset"
+  },
+  "dependencies": {
+    "@nestjs/common": "^10.0.0",
+    "@nestjs/core": "^10.0.0",
+    "@nestjs/platform-express": "^10.0.0",
+    "@nestjs/config": "^3.1.1",
+    "@nestjs/jwt": "^10.2.0",
+    "@nestjs/passport": "^10.0.2",
+    "@nestjs/swagger": "^7.1.17",
+    "@prisma/client": "^5.7.0",
+    "prisma": "^5.7.0",
+    "passport": "^0.7.0",
+    "passport-jwt": "^4.0.1",
+    "passport-google-oauth20": "^2.0.0",
+    "class-validator": "^0.14.0",
+    "class-transformer": "^0.5.1",
+    "bcrypt": "^5.1.1",
+    "helmet": "^7.1.0",
+    "compression": "^1.7.4",
+    "reflect-metadata": "^0.1.13",
+    "rxjs": "^7.8.1",
+    "uuid": "^9.0.1",
+    "stripe": "^14.10.0"
+  },
+  "devDependencies": {
+    "@nestjs/cli": "^10.0.0",
+    "@nestjs/schematics": "^10.0.0",
+    "@nestjs/testing": "^10.0.0",
+    "@types/express": "^4.17.17",
+    "@types/jest": "^29.5.2",
+    "@types/node": "^20.3.1",
+    "@types/supertest": "^2.0.12",
+    "@types/passport-jwt": "^3.0.13",
+    "@types/passport-google-oauth20": "^2.0.14",
+    "@types/bcrypt": "^5.0.2",
+    "@types/uuid": "^9.0.7",
+    "@typescript-eslint/eslint-plugin": "^6.0.0",
+    "@typescript-eslint/parser": "^6.0.0",
+    "eslint": "^8.42.0",
+    "eslint-config-prettier": "^9.0.0",
+    "eslint-plugin-prettier": "^5.0.0",
+    "jest": "^29.5.0",
+    "prettier": "^3.0.0",
+    "source-map-support": "^0.5.21",
+    "supertest": "^6.3.3",
+    "ts-jest": "^29.1.0",
+    "ts-loader": "^9.4.3",
+    "ts-node": "^10.9.1",
+    "tsconfig-paths": "^4.2.1",
+    "typescript": "^5.1.3"
+  },
+  "jest": {
+    "moduleFileExtensions": [
+      "js",
+      "json",
+      "ts"
+    ],
+    "rootDir": "src",
+    "testRegex": ".*\\.spec\\.ts$",
+    "transform": {
+      "^.+\\.(t|j)s$": "ts-jest"
+    },
+    "collectCoverageFrom": [
+      "**/*.(t|j)s"
+    ],
+    "coverageDirectory": "../coverage",
+    "testEnvironment": "node"
+  },
+  "engines": {
+    "node": ">=18.0.0",
+    "npm": ">=8.0.0"
+  }
+}