Function sanitiseEnvVariable

sanitiseEnvVariable(envVars: ProcessEnv, apiKeyOverride?: string): Environment
Validates and sanitizes environment variables for API access.

This function ensures that the required API token is available, either from the environment variables or a command-line override. It prioritizes the command-line provided key over the environment variable.

SECURITY BEST PRACTICES:
- API tokens are validated but never logged in clear text
- Use ConsoleLogger for any logging needs (automatic masking enabled)
- Use sanitizeError() from logger/utils before throwing/logging errors
- Avoid including tokens in error messages or stack traces
- Never expose token length or other metadata in validation messages
Parameters
- envVars: ProcessEnv
  Node.js process environment variables
- OptionalapiKeyOverride: string
  Optional API key provided via command-line (takes precedence)
Returns Environment
Validated Environment object with API_TOKEN
Throws
If neither environment variable nor override provides an API token
Example
```
// Using environment variable
const env = sanitiseEnvVariable(process.env);

// Using command-line override
const env = sanitiseEnvVariable(process.env, 'cli-provided-token');
```
- Defined in EnvironmentController.ts:64