Add Multi-Language Support (i18n)

[Mkalbani]

Description

Support multiple languages for global reach.

Languages to Support (Phase 1)

• English (default)
• Spanish
• French
• Arabic
• Chinese (Simplified)

Acceptance Criteria

• Add Accept-Language header detection
• Translate error messages
• Translate email templates
• GET /api/v1/translations/:lang endpoint
• Store user language preference
• Auto-translate problem/solution content (optional, AI)

Tech Stack

• nestjs-i18n package
• JSON translation files per language

Translation File Structure

src/i18n/
├── en/
│   ├── errors.json
│   ├── emails.json
│   └── common.json
├── es/
│   ├── errors.json
│   └── ...
└── ...

Example Usage

// In service
throw new BadRequestException(
  this.i18n.t('errors.SOLUTION_TOO_SHORT')
);

Challenges

• Managing translation files
• RTL language support (Arabic)
• Date/number formatting
• Content translation (requires AI/human translators)

ETA: 6 hours

[0xNinx]

Hello maintainer, I have reviewed this issue description and acceptance criteria and will like to work on this please. ETA is 6hours.