Add reconnection logic to remote server (#9289)

Migrated from /Users/kevinyang/Documents/GitHub/warp-internal via
`script/migrate-private-to-public`.

## Commits

- 823458b Add reconnect logic to remote server
- 104aafb tech spec
- c4039c3 clippy
- c4e3a39 nit

crates/remote_server/src/transport.rs

@@ -6,13 +6,13 @@
 //! in-process for tests) implement the same trait without touching the
 //! manager.
 //!
-//! Methods are async. Callers use the trait via generics
-//! (`T: RemoteTransport`) rather than `dyn` dispatch.
+//! Returns boxed futures for object safety — the manager stores
+//! `Arc<dyn RemoteTransport>` for reconnection.
 //!
 //! [`RemoteServerManager`]: crate::manager::RemoteServerManager
-use std::future::Future;
 #[cfg(not(target_family = "wasm"))]
 use std::path::PathBuf;
+use std::pin::Pin;
 
 use async_channel::Receiver;
 use warpui::r#async::executor;
@@ -56,12 +56,18 @@ pub struct Connection {
     pub control_path: Option<PathBuf>,
 }
 
-pub trait RemoteTransport: Send + Sync {
+/// Transport abstraction for remote server connections.
+///
+/// Object-safe: returns boxed futures so implementations can be stored
+/// as `Arc<dyn RemoteTransport>` for reconnection.
+pub trait RemoteTransport: Send + Sync + std::fmt::Debug {
     /// Detects the remote host's OS and architecture by running `uname -sm`.
     ///
     /// Returns the parsed [`RemotePlatform`] on success, or an error string
     /// if the command fails or the output cannot be parsed.
-    fn detect_platform(&self) -> impl Future<Output = Result<RemotePlatform, String>> + Send;
+    fn detect_platform(
+        &self,
+    ) -> Pin<Box<dyn std::future::Future<Output = Result<RemotePlatform, String>> + Send>>;
 
     /// Checks whether the remote server binary is present on the remote host.
     ///
@@ -72,7 +78,9 @@ pub trait RemoteTransport: Send + Sync {
     /// Returns `Ok(true)` if the binary is installed and executable,
     /// `Ok(false)` if it is definitively not installed, and
     /// `Err(_)` if the check failed (e.g. SSH timeout/unreachable).
-    fn check_binary(&self) -> impl Future<Output = Result<bool, String>> + Send;
+    fn check_binary(
+        &self,
+    ) -> Pin<Box<dyn std::future::Future<Output = Result<bool, String>> + Send>>;
 
     /// Installs the remote server binary on the remote host.
     ///
@@ -82,7 +90,9 @@ pub trait RemoteTransport: Send + Sync {
     ///
     /// Returns `Ok(())` if the install succeeded, and
     /// `Err(_)` if the install failed (e.g. SSH timeout, script error).
-    fn install_binary(&self) -> impl Future<Output = Result<(), String>> + Send;
+    fn install_binary(
+        &self,
+    ) -> Pin<Box<dyn std::future::Future<Output = Result<(), String>> + Send>>;
 
     /// Establish a new connection to the remote server.
     ///
@@ -96,6 +106,6 @@ pub trait RemoteTransport: Send + Sync {
     /// a socket). Stderr forwarding to local logging should also happen here.
     fn connect(
         &self,
-        executor: &executor::Background,
-    ) -> impl Future<Output = anyhow::Result<Connection>> + Send;
+        executor: std::sync::Arc<executor::Background>,
+    ) -> Pin<Box<dyn std::future::Future<Output = anyhow::Result<Connection>> + Send>>;
 }