Add multi-language support for email and SMS notifications

[Haroldwonder]

Overview\nThe frontend supports EN/ES/FR/PT but the planned notification layer has no internationalization. Notification templates must match the recipient's preferred language.\n\n## Tasks\n- [ ] Store preferred_language on user profile (default: detect from browser Accept-Language)\n- [ ] Add email/SMS template files for EN, ES, FR, PT covering: remittance created, completed, failed, KYC approved, KYC expired\n- [ ] Load template by preferred language in notification service\n- [ ] Fall back to EN if translation is missing\n- [ ] Add CI check that all locales have all template keys\n\n## Acceptance Criteria\n- A Portuguese-speaking user receives all notifications in Portuguese; missing translations fall back to English without errors

[Peolite001]

@Peolite001 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would love to work on this issue

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[nazteeemba]

@nazteeemba has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello, please can I work on this issue?

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[Tobi-8]

@Tobi-8 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

hey danny, i don't know if you'd see this but i have been trying to apply for your issues for a while now, i hope you give me a chance for me to be assigned. Thanks

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[veemakama]

@veemakama has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi, I would love to work on this.

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[Idaonoli]

@Idaonoli has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I'd like to work on this, please

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[GiftedGiftB]

@GiftedGiftB has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I can get this work done in less than 30 minutes.

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[Caneryy]

@Caneryy has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi there, can I work on this issue?

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[David-282]

@David-282 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello maintainer

I'd like to work on this issue. I have experience implementing internationalization (i18n) and backend notification systems. I can add support for storing users' preferred language, implement localized email and SMS templates for EN, ES, FR, and PT, integrate language-aware template selection with an English fallback for missing translations, and add a CI validation to ensure all locales contain the required template keys. This will provide a consistent multilingual notification experience while preventing missing translation issues from reaching production.

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[drips-wave]

Congratulations, @Idaonoli! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @Idaonoli: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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