feat: Add Proficiency level support for Skills and Languages in Mentor Registration

[nora-weisser]

Description

During mentor registration, the API currently allows submitting skills and programming languages as plain lists of values, without any indication of proficiency level. However, the Figma design includes proficiency levels as part of the mentor profile, which creates a mismatch between the frontend design and backend data model.

Current payload example:

"skills": {
  "yearsExperience": 10,
  "areas": ["Quality Assurance"],
  "languages": ["Python", "Javascript", "Java"],
  "mentorshipFocus": ["Switch career to IT"]
}

Issue:

Skills and languages are captured without any proficiency or level (e.g. Expert, Proficient, Experienced, Familiar).

The backend schema does not currently support storing or validating proficiency levels.

This prevents the frontend from fully implementing the designed mentor profile and limits filtering or matching based on skill depth.

Suggested improvement:

Extend the schema to support proficiency levels for skills and/or languages (e.g. structured objects instead of plain strings).

Align the backend model with the Figma design to ensure consistency between UI, API, and stored data.

Example (conceptual):

"languages": [
  { "name": "Python", "level": "Expert" },
  { "name": "JavaScript", "level": "Proficient" }
]

Figma for reference: https://www.figma.com/design/nYZhN7otfli4ry6SJplKRf/WCC-Platform---Phase-1?node-id=60323-36827&t=0UAIvBbiJtKkH7Bk-0