Refactor IPC and DTO structures; remove unused code and streamline message handling

- Removed unused structs and methods from `response.rs`, `usage.rs`, and `client.rs`.
- Simplified `Connection` handling in `conn.rs` to only support Unix sockets.
- Updated `IpcServer` to exclusively use Unix sockets and removed TCP handling.
- Cleaned up `editlog.rs` by removing loading and recent entry methods.
- Refactored `memory.rs` to eliminate unused functions related to lesson promotion and retrospective creation.
- Enhanced `search.rs` to support multiple search providers and improved error handling.
- Updated chat view logic to simplify message display and improve user experience.
- Removed deprecated modules and constants from various files to streamline the codebase.

src/ipc/server.rs

@@ -1,84 +1,20 @@
-use std::net::TcpListener;
 use std::os::unix::net::UnixListener;
-use std::thread;
 use anyhow::Result;
 use super::conn::Connection;
 
-enum ListenerKind {
-    Tcp(TcpListener),
-    Unix(UnixListener),
-}
-
 pub struct IpcServer {
-    listener: ListenerKind,
+    listener: UnixListener,
 }
 
 impl IpcServer {
-    pub fn bind(addr: &str) -> Result<Self> {
-        let listener = TcpListener::bind(addr)?;
-        Ok(IpcServer { listener: ListenerKind::Tcp(listener) })
-    }
-
     pub fn bind_unix(path: &str) -> Result<Self> {
         let _ = std::fs::remove_file(path);
         let listener = UnixListener::bind(path)?;
-        Ok(IpcServer { listener: ListenerKind::Unix(listener) })
+        Ok(IpcServer { listener })
     }
 
     pub fn accept(&self) -> Result<Connection> {
-        match &self.listener {
-            ListenerKind::Tcp(l) => {
-                let (stream, _addr) = l.accept()?;
-                stream.set_nodelay(true)?;
-                Ok(Connection::Tcp(stream))
-            }
-            ListenerKind::Unix(l) => {
-                let (stream, _addr) = l.accept()?;
-                Ok(Connection::Unix(stream))
-            }
-        }
-    }
-
-    pub fn accept_with_handler<F>(self, handler: F) -> thread::JoinHandle<()>
-    where
-        F: Fn(Connection) -> Result<()> + Send + 'static,
-    {
-        match self.listener {
-            ListenerKind::Tcp(l) => {
-                thread::spawn(move || {
-                    for stream in l.incoming() {
-                        match stream {
-                            Ok(s) => {
-                                let _ = s.set_nodelay(true);
-                                if let Err(e) = handler(Connection::Tcp(s)) {
-                                    eprintln!("ipc handler error: {}", e);
-                                }
-                            }
-                            Err(e) => {
-                                eprintln!("ipc accept error: {}", e);
-                                break;
-                            }
-                        }
-                    }
-                })
-            }
-            ListenerKind::Unix(l) => {
-                thread::spawn(move || {
-                    for stream in l.incoming() {
-                        match stream {
-                            Ok(s) => {
-                                if let Err(e) = handler(Connection::Unix(s)) {
-                                    eprintln!("ipc handler error: {}", e);
-                                }
-                            }
-                            Err(e) => {
-                                eprintln!("ipc accept error: {}", e);
-                                break;
-                            }
-                        }
-                    }
-                })
-            }
-        }
+        let (stream, _addr) = self.listener.accept()?;
+        Connection::from_stream(stream)
     }
 }