feat(settings): add locale-aware font preferences

Bundle optional Inter and Outfit families, preserve the platform system default, and provide script-aware fallbacks for every supported locale.

Refs #31

src-tauri/src/ipc.rs

@@ -214,6 +214,23 @@ pub enum Theme {
     Nord,
 }
 
+#[derive(Clone, Debug, Serialize, Deserialize, TS)]
+#[serde(rename_all = "lowercase")]
+#[ts(export, export_to = "../../src/bindings/")]
+pub enum FontFamily {
+    System,
+    Inter,
+    Outfit,
+    Serif,
+    Monospace,
+}
+
+impl Default for FontFamily {
+    fn default() -> Self {
+        Self::System
+    }
+}
+
 #[derive(Clone, Debug, Serialize, Deserialize, TS)]
 #[serde(rename_all = "lowercase")]
 #[ts(export, export_to = "../../src/bindings/")]
@@ -312,6 +329,8 @@ pub struct SchedulerSettings {
 pub struct PersistedSettings {
     pub theme: Theme,
     #[serde(default)]
+    pub font_family: FontFamily,
+    #[serde(default)]
     pub window_control_style: WindowControlStyle,
     #[serde(default)]
     pub calendar_preference: CalendarPreference,