Fix code issues and add missing documentation

- Fix duplicate tenant_id parameter in seed.py (line 148)
- Add security warning to SECRET_KEY in .env.example
- Create comprehensive README.md with setup instructions
- Add Alembic configuration files (alembic.ini, env.py, script.py.mako)
- Create initial database migration for all tables
- Document project structure, features, and deployment checklist

backend/.env.example

@@ -3,6 +3,8 @@ DATABASE_URL=postgresql+asyncpg://trustos:trustos_dev@postgres:5432/trustos
 SYNC_DATABASE_URL=postgresql://trustos:trustos_dev@postgres:5432/trustos
 
 # Auth
+# IMPORTANT: Generate a secure random key in production using: openssl rand -hex 32
+# Never use the default value in production environments
 SECRET_KEY=changeme-use-openssl-rand-hex-32-in-production
 ACCESS_TOKEN_EXPIRE_MINUTES=480