Feature Flag Manager

# 1. Create a feature flag
node flag.js create dark-mode --description "Dark theme UI"
2. Enable for 10% of users
node flag.js update dark-mode --percentage 10
3. Check if enabled for current user
node flag.js enabled dark-mode --user-id alice
→ true (or false based on percentage)
4. Gradually increase to 100%
node flag.js update dark-mode --percentage 50
node flag.js update dark-mode --percentage 100

Flags stored in .featureflags/config.json:

{
  "flags": {
    "dark-mode": {
      "enabled": true,
      "percentage": 25,
      "description": "Dark theme support"
    },
    "pricing-test": {
      "enabled": true,
      "percentage": 100,
      "variants": ["control", "v1", "v2"],
      "weights": [50, 25, 25]
    }
  }
}