Function isSensitiveKey

isSensitiveKey(key: string): boolean
Check if a field/key name is sensitive and should be redacted.

Algorithm (4 steps):
1. Check if the key contains any sensitive pattern (substring match)
2. If the entire key is an exact blocklist word → not sensitive
3. For compound keys (segments): only sensitive if at least one segment is genuinely sensitive (not fully explained by blocklist)
4. Single-segment keys: check blocklist patterns
Parameters
- key: string
  The field name to check
Returns boolean
true if the key should be redacted
Example
```
isSensitiveKey('password')         // true
isSensitiveKey('api_key')          // true
isSensitiveKey('keyboard')         // false (blocklisted)
isSensitiveKey('monkey')           // false (blocklisted)
isSensitiveKey('monkey_password')  // true  ("password" is genuine)
```
- Defined in src/utils/sensitive-keys.ts:117