refactor: src-tauri 重命名为 gui

Tauri CLI 自动检测 workspace 成员，构建不受影响。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

gui/src/commands/disabled.rs

@@ -0,0 +1,6 @@
+use path_editor_core::disabled;
+
+#[tauri::command]
+pub fn save_disabled_state(system: Vec<String>, user: Vec<String>) -> Result<(), String> { disabled::save_disabled_state(system, user) }
+#[tauri::command]
+pub fn load_disabled_state() -> Result<(Vec<String>, Vec<String>), String> { disabled::load_disabled_state() }