Remove netcat dependency (#28920)

Closes #28813
Closes #27749

Release Notes:

- Removed the need to have openbsd `netcat` (`nc`) installed on your
system in order to enter passwords for `git` or `ssh` (remote
development). If you previously installed `netcat` specifically for Zed,
you may uninstall it.

crates/zed/Cargo.toml

@@ -18,6 +18,7 @@ path = "src/main.rs"
 activity_indicator.workspace = true
 agent.workspace = true
 anyhow.workspace = true
+askpass.workspace = true
 assets.workspace = true
 assistant.workspace = true
 assistant_context_editor.workspace = true

crates/zed/src/main.rs

@@ -180,6 +180,11 @@ fn main() {
 
     let args = Args::parse();
 
+    if let Some(socket) = &args.askpass {
+        askpass::main(socket);
+        return;
+    }
+
     // Set custom data directory.
     if let Some(dir) = &args.user_data_dir {
         paths::set_custom_data_dir(dir);
@@ -1002,6 +1007,11 @@ struct Args {
     #[arg(long)]
     system_specs: bool,
 
+    /// Used for SSH/Git password authentication, to remove the need for netcat as a dependency,
+    /// by having Zed act like netcat communicating over a Unix socket.
+    #[arg(long, hide = true)]
+    askpass: Option<String>,
+
     /// Run zed in the foreground, only used on Windows, to match the behavior of the behavior on macOS.
     #[arg(long)]
     #[cfg(target_os = "windows")]