feat: add admin/profile UI, i18n (fr/de/pt), fix CI pipelines

- Add admin panel link and profile modal in user menu dropdown
- Add French, German and Portuguese locale support (full translations)
- Register new locales across JS frontend and Rust backend
- Create CI pipeline (fmt, clippy, test, audit, build)
- Fix docker-build.yml (cache, real tests, reduced timeout)
- Fix docker-publish.yml (multi-arch via QEMU, latest tag, pre-publish tests)
- Add dependabot.yml for automated dependency updates

src/application/dtos/i18n_dto.rs

@@ -16,6 +16,9 @@ impl From<Locale> for LocaleDto {
         let (code, name) = match locale {
             Locale::English => ("en", "English"),
             Locale::Spanish => ("es", "Español"),
+            Locale::French => ("fr", "Français"),
+            Locale::German => ("de", "Deutsch"),
+            Locale::Portuguese => ("pt", "Português"),
         };
         
         Self {