feat(agentcompany-rust): scaffold native shell and runtime bridge

AgentCompany-Rust/crates/app_models/src/state.rs

@@ -0,0 +1,22 @@
+use domain::SectionId;
+
+#[derive(Clone, Debug, Default)]
+pub struct AppState {
+    pub section: SectionId,
+    pub selected_run_id: Option<String>,
+    pub selected_approval_id: Option<String>,
+    pub selected_message_id: Option<String>,
+    pub selected_document_id: Option<String>,
+    pub selected_workspace_id: Option<String>,
+    pub status_line: Option<String>,
+}
+
+impl AppState {
+    pub fn set_status(&mut self, value: impl Into<String>) {
+        self.status_line = Some(value.into());
+    }
+
+    pub fn clear_status(&mut self) {
+        self.status_line = None;
+    }
+}