remote: Fix missing path escaping in SFTP upload (#62239)

# Objective

- Fixes #62238
- Properly escapes paths in the sftp PUT line

## Solution

- 10-line wrapper function that escapes paths as sftp expects. Namely:
paths in quotes with `\\` and `"` escaped.

## Testing

- Did you test these changes? If so, how? `cargo check`
- Are there any parts that need more testing? Up to you, this is a
simple change and I dont think sftp with default install paths ever
worked on MacOS
- How can other people (reviewers) test your changes? Is there anything
specific they need to know? Just connect to a remote on OSX and see if
the logs had an sftp upload failure in there
- If relevant, what platforms did you test these changes on, and are
there any important ones you can't test?

## Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content adheres to Zed's UI standards
([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
and
[icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md)
guidelines)
- [ ] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

---

Release Notes:

- Fix remote uploads over sftp where the paths contain spaces

---------

Co-authored-by: Smit Barmase <heysmitbarmase@gmail.com>

crates/remote/src/transport/ssh.rs

@@ -112,6 +112,27 @@ fn bracket_ipv6(host: &str) -> String {
     }
 }
 
+// Quote paths for sftp batch parsing and double backslashes for POSIX glob();
+// Win32-OpenSSH accepts the same encoding.
+fn escape_sftp_path(path: &str) -> String {
+    let mut escaped = String::with_capacity(path.len() + 2);
+    escaped.push('"');
+    for character in path.chars() {
+        if character == '"' || character == '\\' {
+            escaped.push('\\');
+        }
+        escaped.push(character);
+    }
+    escaped.push('"');
+    escaped
+}
+
+fn sftp_put_command(source_path: &str, destination_path: &str) -> String {
+    let source = escape_sftp_path(source_path);
+    let destination = escape_sftp_path(destination_path);
+    format!("put {source} {destination}\n")
+}
+
 #[derive(Debug, Default, Clone, PartialEq, Eq, Hash, serde::Serialize, serde::Deserialize)]
 pub struct SshConnectionOptions {
     pub host: SshConnectionHost,
@@ -1230,7 +1251,7 @@ impl SshRemoteConnection {
         if Self::is_sftp_available().await {
             log::debug!("using SFTP for file upload");
             let mut command = self.build_sftp_command();
-            let sftp_batch = format!("put {src_path_display} {dest_path_str}\n");
+            let sftp_batch = sftp_put_command(&src_path_display, &dest_path_str);
 
             let mut child = command.spawn()?;
             if let Some(mut stdin) = child.stdin.take() {
@@ -2175,6 +2196,58 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn test_sftp_put_command_quotes_paths() {
+        assert_eq!(
+            sftp_put_command(
+                "/tmp/Zed Repro/remote_server",
+                ".zed_server/downloaded server",
+            ),
+            "put \"/tmp/Zed Repro/remote_server\" \".zed_server/downloaded server\"\n"
+        );
+    }
+
+    #[test]
+    fn test_sftp_put_command_escapes_quotes_in_paths() {
+        assert_eq!(
+            sftp_put_command(
+                r#"/tmp/Zed "Nightly"/remote_server"#,
+                ".zed_server/remote_server",
+            ),
+            "put \"/tmp/Zed \\\"Nightly\\\"/remote_server\" \".zed_server/remote_server\"\n"
+        );
+    }
+
+    #[test]
+    fn test_sftp_put_command_doubles_trailing_destination_backslash_before_closing_quote() {
+        assert_eq!(
+            sftp_put_command("/tmp/remote_server", r"C:\zed server\"),
+            "put \"/tmp/remote_server\" \"C:\\\\zed server\\\\\"\n"
+        );
+    }
+
+    #[test]
+    fn test_sftp_put_command_doubles_source_backslashes_for_posix_glob() {
+        assert_eq!(
+            sftp_put_command(
+                r"/tmp/zed\server/remote_server",
+                ".zed_server/remote_server",
+            ),
+            "put \"/tmp/zed\\\\server/remote_server\" \".zed_server/remote_server\"\n"
+        );
+    }
+
+    #[test]
+    fn test_sftp_put_command_doubles_windows_source_backslashes_on_all_platforms() {
+        assert_eq!(
+            sftp_put_command(
+                r"C:\Users\Smit\Zed Repro\remote_server",
+                ".zed_server/remote_server",
+            ),
+            "put \"C:\\\\Users\\\\Smit\\\\Zed Repro\\\\remote_server\" \".zed_server/remote_server\"\n"
+        );
+    }
+
     #[test]
     fn scp_args_exclude_port_forward_flags() {
         let options = SshConnectionOptions {