feat: implement Viswam internship signup page

Description

This merge request implements a two-step signup flow that separates basic registration from profile completion, along with new internship-specific profile fields and English language support.

Changes

Authentication

• Step 1 signup: Creates user with minimal fields (phone, username, name, password, consent)
• Step 2 profile completion: New /auth/complete-profile endpoint to add optional profile details
• Login response: Returns TokenResponse with user_id, username, phone, profile_complete, and roles
• Email uniqueness check moved to profile completion step

User Model

• Made gender, date_of_birth, current_place optional (previously required)
• Added profile_complete boolean flag
• Added internship-specific fields:
  • organisation_type, work_location, rural_area_access
  • permanent_postal_address, college_institution, education_category
  • specific_stream, current_year_of_study, college_roll_number
  • task_registered_id, internship_languages
  • has_laptop, laptop_os, laptop_ram, mobile_os, mobile_ram
  • internet_speed, daily_data_limit
  • has_completed_ai_courses, ai_courses_list
• Replaced resume_path with resume_record_id (FK to record table)

Database Migrations

• Adds 23 new columns to user table
• Adds English to allowed language values for records
• Drops work_location_address column

Language Support

• Added english to the Language enum

Checklist

• The feature has been fully implemented.
• Tests for the new feature are included and passing.
• User documentation/guides have been updated (if applicable).
• Impact on existing functionality has been considered.

Related Issue(s)

Closes #116 (closed)