feat: profile customization (bio, department, year)

[ammaarrahmed]

Summary

Expand user profiles with meaningful academic metadata and editable personal context.

Scope

• Extend profile schema with bio, department, and year fields.
• Add edit profile UI with validation and safe updates.
• Display added fields in the profile screen.

Acceptance Criteria

• Users can update profile metadata successfully.
• Validation blocks invalid or incomplete required values.
• Existing profile documents remain backward-compatible.

Roadmap Link

Phase 3 -> Profile Customization