feat(ui): persist window state and clarify transfer telemetry

- Persist bounded logical main-window geometry with work-area-safe startup restoration.
- Persist the Folders collapse preference in SQLite with guarded legacy localStorage migration.
- Keep media transfer telemetry truthful and compact the transfer controls across locales.
- Add bridge, presentation, persistence, geometry, and configuration regression coverage.

src-tauri/src/ipc.rs

@@ -653,6 +653,14 @@ pub struct SchedulerSettings {
     pub post_queue_action: PostQueueAction,
 }
 
+#[derive(Clone, Debug, Serialize, Deserialize, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export, export_to = "../../src/bindings/")]
+pub struct MainWindowSize {
+    pub width: u32,
+    pub height: u32,
+}
+
 #[derive(Clone, Debug, Serialize, Deserialize, TS)]
 #[serde(rename_all = "camelCase")]
 #[ts(export, export_to = "../../src/bindings/")]
@@ -678,6 +686,11 @@ pub struct PersistedSettings {
     pub speed_limit_preset_values: Vec<f64>,
     pub logs_enabled: bool,
     pub is_sidebar_visible: bool,
+    #[serde(default)]
+    pub is_folders_collapsed: bool,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    #[ts(optional)]
+    pub main_window_size: Option<MainWindowSize>,
     #[serde(default = "default_sidebar_position")]
     pub sidebar_position: String,
     pub active_settings_tab: SettingsTab,