Add README and technical docs

- README with quick start, package overview, links to docs
- docs/setup.md — prerequisites, env vars, installation, running, testing
- docs/architecture.md — monorepo structure, backend/frontend design
- docs/api.md — full endpoint reference with permissions
- docs/database.md — schema overview, migrations, multi-tenancy
- docs/testing.md — test runner, suites, writing tests
- Updated .env.example with all supported variables

docs/setup.md

@@ -0,0 +1,89 @@
+# Development Setup
+
+## Prerequisites
+
+- [Bun](https://bun.sh) v1.1+
+- PostgreSQL 16
+- Valkey 8 (or Redis 7+)
+
+## Installation
+
+```bash
+git clone <repo-url> && cd forte
+bun install
+```
+
+## Environment
+
+Create a `.env` file in the project root:
+
+```env
+DATABASE_URL=postgresql://forte:forte@localhost:5432/forte
+REDIS_URL=redis://localhost:6379
+JWT_SECRET=your-secret-here
+NODE_ENV=development
+```
+
+### All Environment Variables
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `DATABASE_URL` | `postgresql://forte:forte@localhost:5432/forte` | PostgreSQL connection string |
+| `REDIS_URL` | `redis://localhost:6379` | Valkey/Redis connection string |
+| `JWT_SECRET` | (auto-generated in dev) | Secret for signing JWTs. **Required in production.** |
+| `PORT` | `8000` | Backend API port |
+| `HOST` | `0.0.0.0` | Backend bind address |
+| `NODE_ENV` | — | `development`, `test`, or `production` |
+| `LOG_LEVEL` | `info` | Pino log level (`debug`, `info`, `warn`, `error`, `silent`) |
+| `LOG_FILE` | — | Path to log file (production only, also logs to stdout) |
+| `STORAGE_PROVIDER` | `local` | File storage provider (`local` or `s3`) |
+| `STORAGE_LOCAL_PATH` | `./data/files` | Local file storage directory |
+| `CORS_ORIGINS` | `*` (dev) | Comma-separated allowed origins |
+| `APP_URL` | `http://localhost:5173` | Frontend URL (used in password reset links) |
+
+## Database
+
+```bash
+# Create the database
+createdb forte
+
+# Run migrations
+cd packages/backend
+source ../.env  # or source .env from project root
+bunx drizzle-kit migrate
+```
+
+## Running
+
+```bash
+# From project root — starts all packages
+bun run dev
+
+# Or individually:
+cd packages/backend && source .env && bun run dev   # API on :8000
+cd packages/admin && bun run dev                     # UI on :5173
+```
+
+## Testing
+
+```bash
+# API integration tests (starts a backend, seeds DB, runs HTTP tests)
+cd packages/backend
+source .env
+bun run api-test
+
+# Filter by suite or tag
+bun run api-test --suite accounts
+bun run api-test --tag crud
+
+# Unit tests
+bun run test
+```
+
+## Useful Commands
+
+```bash
+bun run lint      # ESLint across all packages
+bun run format    # Prettier write
+bun run build     # Build all packages
+```