feat: add persistent server-client sessions

   Make herdr persistent by default.

   Launching herdr now starts or reattaches to a background session
   server. Clients can detach and reattach while panes and agent
   processes keep running. Session mode now supports multi-client attach,
   auto-detect startup, and a thin-client/headless-server split.

   This also refactors the large app, ui, input, pane, config,
   workspace, and persistence modules into smaller focused submodules,
   while preserving behavior and colocating tests with the code they
   exercise.

   Upgrade notes:
   - persistence mode is now the default
   - in-app quit detaches the current client instead of stopping the server
   - use `herdr server stop` to stop the background session
   - use `--no-session` for the old single-process behavior
   - default socket paths now live under the config directory

1 files changed, 1 insertions, 1 deletions

diff --git a/src/events.rs b/src/events.rs
index dd433d55..1d90ac32 100644
--- a/src/events.rs
+++ b/src/events.rs
@@ -37,7 +37,7 @@ pub enum AppEvent {
         agent_label: String,
         known_agent: Option<Agent>,
     },
-    /// A new version was downloaded and installed. Restart to use it.
+    /// A new version is available and ready to install explicitly.
     UpdateReady { version: String },
     /// A pane child emitted a valid OSC 52 clipboard write. The main loop
     /// re-emits it through herdr's own clipboard writer.