Refactor repeated PRINCIPAL_ROLE string literal into a shared constant

### Is your feature request related to a problem? Please describe.

### Problem

The string literal "PRINCIPAL_ROLE:" appears multiple times in the codebase.

Using a shared constant would improve maintainability and reduce duplication.

### Proposed Solution

Introduce a constant such as:

private static final String PRINCIPAL_ROLE_PREFIX = "PRINCIPAL_ROLE:";

and replace direct usages of the literal.

### Benefits

- Improved maintainability
- Reduced duplication
- Easier future modifications

### Describe the solution you'd like

The string literal "PRINCIPAL_ROLE:" is currently repeated in multiple locations.

To improve maintainability and reduce duplication, introduce a shared constant such as:

private static final String PRINCIPAL_ROLE_PREFIX = "PRINCIPAL_ROLE:";

and replace direct usages of the literal with the constant.

### Describe alternatives you've considered

An alternative is to keep the existing string literals as-is since the current implementation functions correctly.

However, extracting the value into a shared constant improves maintainability and reduces the risk of inconsistencies if the prefix needs to be modified in the future.

### Additional context

This is a small code quality and maintainability improvement with no expected behavioral changes.

Search the codebase for the repeated "PRINCIPAL_ROLE:" literal and inspect the surrounding usages to identify the appropriate shared scope. Replace the direct usages with one constant, then run the relevant project checks to confirm behavior is unchanged.

Written by the indexing model from the issue text.