add test UFC with 10,000 flags, matching test cases and validation

[leoromanovsky]

Motivation

Our current test suite contains 19 flags with carefully crafted test cases. While excellent for functional testing, we need to validate SDK performance and correctness at scale to ensure production readiness with enterprise customers who may have 1,000+ feature flags.

Generated tests supplement (not replace) existing hand-crafted tests

👉 Hand-crafted tests in ufc/tests/ remain the canonical demonstrations of SDK functionality

Changes

1. Flag Generator (generate-flags.ts)

• TypeScript CLI tool that generates realistic large-scale flag configurations
• Configurable output: 1 to 10,000 flags with custom output directories
• Realistic targeting: Geographic, demographic, technical attribute rules
• All variation types: STRING, INTEGER, BOOLEAN, NUMERIC, JSON
• Complex operators: ONE_OF, MATCHES, LT/GT comparisons, IS_NULL
• Traffic allocation: Proper shard-based A/B testing setup

npx ts-node generate-flags.ts 2000 ufc/ # Generate 2K flags