refactor: render the shell in the client (#3487)

* feat: add opt-in client-rendered shell

* feat: add client-owned shell mouse controls

* feat: complete client-owned shell chrome

* feat: add client-owned shell settings and notifications

* feat: run client shell custom commands

* feat: render popup terminals in client shell

* feat: add client-owned scrollback and copy mode

* fix: preserve client worktree trust defaults

* feat: render startup diagnostics in client shell

* feat: render onboarding in client shell

* feat: render product announcements in client shell

* feat: render release notes in client shell

* feat: render mobile switcher in client shell

* feat: render kitty graphics in client shell

* fix: preserve client shell lifecycle coherence

* refactor: route client shell commands through endpoint connections

* refactor: make the client-rendered shell the default

* refactor: remove monolithic launch mode

* refactor: complete client-rendered shell cutover

* perf: retain client pane surface updates

* perf: scale retained pane surface updates

* perf: remove remote pane input latency

* test: make client shell checks platform-independent

* fix: prevent client timer starvation

* test: fix client shell platform gates

* test: accept retained surfaces in cross-area checks

* test: make client mode assertions platform-neutral

* fix: badge only outdated integrations

1 files changed, 5 insertions, 177 deletions

diff --git a/src/main.rs b/src/main.rs
index a6ba1c03..91a6b2e4 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,13 +1,5 @@
 use std::io;
 
-use crossterm::event::{
-    DisableBracketedPaste, DisableFocusChange, DisableMouseCapture, EnableBracketedPaste,
-    EnableFocusChange, EnableMouseCapture,
-};
-#[cfg(not(windows))]
-use crossterm::event::{PopKeyboardEnhancementFlags, PushKeyboardEnhancementFlags};
-use crossterm::execute;
-
 pub(crate) const HERDR_ENV_VAR: &str = "HERDR_ENV";
 pub(crate) const HERDR_ENV_VALUE: &str = "1";
 const NESTED_HERDR_MESSAGES: [&str; 6] = [
@@ -19,41 +11,6 @@ const NESTED_HERDR_MESSAGES: [&str; 6] = [
     "recursion detected. base case not found. aborting.",
 ];
 
-#[cfg(not(windows))]
-fn push_keyboard_enhancement_flags() -> io::Result<()> {
-    execute!(
-        io::stdout(),
-        PushKeyboardEnhancementFlags(crate::input::ime_compatible_keyboard_enhancement_flags())
-    )
-}
-
-#[cfg(windows)]
-fn push_keyboard_enhancement_flags() -> io::Result<()> {
-    Ok(())
-}
-
-#[cfg(not(windows))]
-fn pop_keyboard_enhancement_flags() -> io::Result<()> {
-    execute!(io::stdout(), PopKeyboardEnhancementFlags)
-}
-
-#[cfg(windows)]
-fn pop_keyboard_enhancement_flags() -> io::Result<()> {
-    Ok(())
-}
-
-fn set_host_color_scheme_reports(enabled: bool) -> io::Result<()> {
-    use std::io::Write;
-
-    let sequence = if enabled {
-        crate::terminal_theme::HOST_COLOR_SCHEME_REPORT_ENABLE_SEQUENCE
-    } else {
-        crate::terminal_theme::HOST_COLOR_SCHEME_REPORT_DISABLE_SEQUENCE
-    };
-    io::stdout().write_all(sequence.as_bytes())?;
-    io::stdout().flush()
-}
-
 mod agent_resume;
 mod api;
 mod app;
@@ -62,6 +19,7 @@ mod checksum;
 mod cli;
 mod client;
 mod config;
+mod copy_mode;
 mod detect;
 mod events;
 mod ghostty;
@@ -103,10 +61,6 @@ mod update;
 mod workspace;
 mod worktree;
 
-fn init_logging() {
-    crate::logging::init_file_logging("herdr.log");
-}
-
 const DEFAULT_CONFIG: &str = r##"# herdr configuration
 # Place this file at ~/.config/herdr/config.toml
 
@@ -718,7 +672,6 @@ fn main() -> io::Result<()> {
         println!("  {:<32} Run as headless server", "herdr server");
         println!();
         println!("Options:");
-        println!("  --no-session        Run monolithically (no server/client, escape hatch)");
         println!("  --session <name>    Use or create a named persistent session");
         println!("  --remote <target>   Attach through SSH to a remote Herdr server");
         println!("  --remote-keybindings <local|server>");
@@ -758,7 +711,6 @@ fn main() -> io::Result<()> {
 
     // Reject unknown flags
     let known_flags = [
-        "--no-session",
         "--session",
         "--remote",
         "--remote-keybindings",
@@ -812,135 +764,11 @@ fn main() -> io::Result<()> {
     let loaded_config = config::Config::load();
     exit_if_nested_disabled(&loaded_config.config);
 
-    let no_session = args.iter().any(|a| a == "--no-session");
-
-    // Auto-detect launch: when --no-session is NOT set, use server/client mode.
-    // Check if a server is running, spawn one if needed, then attach as client.
-    if !no_session {
-        if let Err(err) = server::autodetect::auto_detect_launch() {
-            eprintln!("herdr: {err}");
-            std::process::exit(1);
-        }
-        return Ok(());
+    if let Err(err) = server::autodetect::auto_detect_launch() {
+        eprintln!("herdr: {err}");
+        std::process::exit(1);
     }
-
-    // --- Monolithic mode (--no-session escape hatch) ---
-    // This is the pre-mission single-process behavior.
-
-    init_logging();
-
-    let (api_tx, api_rx) = tokio::sync::mpsc::unbounded_channel();
-    let event_hub = api::EventHub::default();
-    let _api_server = match api::start_server_with_capabilities(api_tx, event_hub.clone(), None) {
-        Ok(server) => server,
-        Err(err) if err.kind() == io::ErrorKind::AddrInUse => {
-            eprintln!("error: herdr is already running");
-            eprintln!("socket: {}", api::socket_path().display());
-            std::process::exit(1);
-        }
-        Err(err) => return Err(err),
-    };
-
-    let modify_other_keys_mode = crate::input::host_modify_other_keys_mode();
-
-    let original_hook = std::panic::take_hook();
-    let panic_resets_modify_other_keys = modify_other_keys_mode.is_some();
-    std::panic::set_hook(Box::new(move |info| {
-        tracing::error!("PANIC: {info}");
-        if panic_resets_modify_other_keys {
-            let _ = std::io::Write::write_all(&mut io::stdout(), b"\x1b[>4;0m");
-        }
-        if crate::kitty_graphics::is_enabled() {
-            let _ = crate::kitty_graphics::clear_all_host_graphics();
-        }
-        let _ = execute!(
-            io::stdout(),
-            DisableFocusChange,
-            DisableBracketedPaste,
-            DisableMouseCapture
-        );
-        let _ = crate::terminal_modes::clear_host_mouse_reporting(&mut io::stdout());
-        let _ = set_host_color_scheme_reports(false);
-        let _ = pop_keyboard_enhancement_flags();
-        ratatui::restore();
-        original_hook(info);
-    }));
-
-    let config = &loaded_config.config;
-    let config_diagnostic = config::config_diagnostic_summary(&loaded_config.diagnostics);
-    logging::startup("app");
-
-    // Background update check (non-blocking, best-effort)
-    // Only checks for newer versions and notifies the TUI.
-    // Skipped in --no-session mode (testing).
-
-    let rt = tokio::runtime::Builder::new_multi_thread()
-        .enable_all()
-        .build()
-        .expect("failed to create tokio runtime");
-
-    let result = rt.block_on(async {
-        let mut terminal = ratatui::init();
-        crate::terminal_modes::clear_host_mouse_reporting(&mut io::stdout())?;
-        if config.ui.mouse_capture {
-            execute!(io::stdout(), EnableMouseCapture)?;
-        } else {
-            execute!(io::stdout(), DisableMouseCapture)?;
-        }
-        execute!(io::stdout(), EnableBracketedPaste, EnableFocusChange)?;
-        set_host_color_scheme_reports(true)?;
-        push_keyboard_enhancement_flags()?;
-
-        // Some hosts do not honor Kitty keyboard enhancement pushes for
-        // Shift+Enter. Enable xterm modifyOtherKeys only on hosts where we
-        // know it is needed and parseable, so modified Enter stays distinct.
-        if let Some(mode) = modify_other_keys_mode {
-            use std::io::Write;
-            std::io::stdout().write_all(mode.set_sequence())?;
-            std::io::stdout().flush()?;
-        }
-
-        let mut app = app::App::new(
-            config,
-            true, // no_session — monolithic mode never saves/restores sessions
-            config_diagnostic,
-            api_rx,
-            event_hub,
-        );
-        let result = app.run(&mut terminal).await;
-
-        // Reset modifyOtherKeys if we enabled it.
-        if modify_other_keys_mode.is_some() {
-            use std::io::Write;
-            std::io::stdout().write_all(b"\x1b[>4;0m")?;
-            std::io::stdout().flush()?;
-        }
-
-        if crate::kitty_graphics::is_enabled() {
-            crate::kitty_graphics::clear_all_host_graphics()?;
-        }
-        pop_keyboard_enhancement_flags()?;
-        execute!(
-            io::stdout(),
-            DisableFocusChange,
-            DisableBracketedPaste,
-            DisableMouseCapture
-        )?;
-        crate::terminal_modes::clear_host_mouse_reporting(&mut io::stdout())?;
-        set_host_color_scheme_reports(false)?;
-        ratatui::restore();
-
-        // Drop app (and all workspaces/panes) before runtime shuts down
-        drop(app);
-
-        result
-    });
-
-    // Shut down runtime immediately — kills lingering PTY reader/writer tasks
-    rt.shutdown_timeout(std::time::Duration::from_millis(100));
-
-    logging::shutdown("app");
-    result
+    Ok(())
 }
 
 #[cfg(test)]