[P3] Internationalization (i18n) infrastructure

[hazeliscoding]

Problem

The target audience (anime fans) is global. No i18n infrastructure exists. Even shipping English-only, wiring up i18n early avoids a painful retrofit.

Requirements

• Set up @ngx-translate or Angular built-in i18n
• Extract all user-facing strings into translation files
• Default locale: English
• Structure translation files by feature module

Acceptance Criteria

• All user-facing strings come from translation files, not hardcoded
• Adding a new language requires only a new translation file
• Date and number formatting respects locale

References

• Roadmap §12 — Frontend Engineering