[TASK-016] Profile Management with Tests

[dwalleck]

Implement profile save/load functionality using TDD.

Success Criteria

• Write profile tests first
• Profile CRUD operations
• Quick presets available
• Import/export working
• Profile switching smooth
• All tests passing

TDD Approach

• Test CRUD operations
• Test profile validation
• Test preset values
• Mock file operations

Dependencies

• Depends on: TASK-013, TASK-015