feat: phase 2 — i18n messages EN/FR (--lang, AM_LANG/LANG, catalogue tr/tr_fmt, REPL lang) (closes #74)

src/app.rs

@@ -21,6 +21,9 @@ pub struct App {
     pub catalog: Catalog,
     pub state: StateStore,
     pub log: Logger,
+    /// Active output language (issue #74); mirrored in i18n::active() so the
+    /// REPL 'lang' command can switch it at runtime.
+    lang: Cell<crate::i18n::Lang>,
     /// Active output color theme (switchable at runtime with the REPL
     /// 'theme <name>' command).
     theme: Cell<&'static Theme>,
@@ -84,6 +87,8 @@ impl App {
             loaded.config.groups.clone(),
         );
         let theme = resolve_theme(cli.theme.as_deref(), loaded.config.settings.theme.as_deref())?;
+        let lang = crate::i18n::resolve(cli.lang);
+        crate::i18n::set_lang(lang);
         Ok(Self {
             cli,
             config: loaded.config,
@@ -92,6 +97,7 @@ impl App {
             catalog,
             state,
             log,
+            lang: Cell::new(lang),
             theme: Cell::new(theme),
         })
     }
@@ -116,6 +122,18 @@ impl App {
         self.theme.get()
     }
 
+    /// Active output language (issue #74).
+    pub fn lang(&self) -> crate::i18n::Lang {
+        self.lang.get()
+    }
+
+    /// Switch the active language (REPL 'lang' command); the i18n global is
+    /// kept in sync so tr()/tr_fmt! follow immediately.
+    pub fn set_lang(&self, lang: crate::i18n::Lang) {
+        self.lang.set(lang);
+        crate::i18n::set_lang(lang);
+    }
+
     /// Switch the active theme (used by the REPL 'theme <name>' command).
     pub fn set_theme(&self, theme: &'static Theme) {
         self.theme.set(theme);