feat(ipc): dukung Ctrl+Y clipboard copy di mode daemon/attach

Tambah DaemonFrame::ClipboardCopy(String) supaya daemon bisa
mengirim teks pending_clipboard_copy ke attach client, yang
kemudian menulis sekuens OSC52 ke stdout-nya sendiri (bukan
stdout daemon yang tidak dimiliki terminal user).

src/ipc/protocol.rs

@@ -91,5 +91,6 @@ pub enum DaemonFrame {
     StateUpdate(Box<StatePayload>),
     StreamToken(String),
     SystemNote { kind: String, message: String },
+    ClipboardCopy(String),
     Closed,
 }

src/main.rs

@@ -396,6 +396,9 @@ fn handle_daemon_client(
                         running = false;
                     }
                 }
+                if let Some(text) = state.misc.pending_clipboard_copy.take() {
+                    conn.send(&ipc::protocol::DaemonFrame::ClipboardCopy(text))?;
+                }
                 send_daemon_update(&mut conn, state)?;
             }
             None => {
@@ -583,6 +586,15 @@ fn run_attach(session_id: &str) -> Result<()> {
                     ),
                 );
             }
+            Some(ipc::protocol::DaemonFrame::ClipboardCopy(text)) => {
+                let _ = write_osc52(&mut io::stdout(), &text);
+                client_state.push_toast(
+                    app::state::types::Toast::new(
+                        app::state::types::ToastKind::Success,
+                        "Copied to clipboard".to_string(),
+                    ),
+                );
+            }
             Some(ipc::protocol::DaemonFrame::Closed) | None => {
                 client_state.quit = true;
             }