Add backend domain services, Prisma schema/migration, API routes, Next.js demo frontend, and test suite

[deesemailfortesting-eng]

Motivation

• Provide a private prototype demonstrating agent-driven league mechanics with controlled agent-to-agent payments and protocol guardrails.
• Enable deterministic simulation mode and LLM-agnostic provider abstractions for demos and tests.
• Ship a small Next.js demo UI to explore league state, agents, matchups, wallets, messages, and admin controls.

Description

• Added a complete backend: Fastify app (src/app.ts, src/index.ts), Prisma client (src/db/prisma.ts), configuration (src/config/env.ts), full domain services (src/services/*) for leagues, wallets, escrows, settlements, messages, moderation, agent tools, ledger, and provider abstractions (src/providers/*).
• Introduced job runners and simulator (src/jobs/*, src/simulation/simulator.ts) plus CLIs for reset, simulate, and run jobs (src/cli/*).
• Added Prisma schema, SQL migration, and seed data (prisma/schema.prisma, prisma/migrations/*, prisma/seed.ts) and DB helper scripts in package.json.
• Built a minimal Next.js frontend demo with pages, components, API client, styles, and config (frontend/*) and exposed interactive admin controls (frontend/components/AdminPanel.tsx).
• Improved docs and dev setup with README.md, .env.example, .gitignore tweak to include the example env, top-level package.json and frontend/package.json, TypeScript and Vitest configs, and a comprehensive test suite (tests/*).

Testing

• Ran the automated unit and integration test suite with npm test (Vitest) which executed the tests in tests/ including service unit tests, job behavior tests, provider fallbacks, and frontend smoke checks, and the suite passed.
• Exercised job and simulator flows via CLI-style invocations in tests (simulate:week, jobs:run) to validate deterministic scoring, escrow locking idempotency, forfeits, and settlement idempotency.
• Included a frontend smoke test that verifies the presence of key Next.js pages and an API route presence check performed via buildApp() injection.

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Codex Task