memoryd, proto, brokerd, bxctl: repeated error lines written once

Implemented-By: OpenCode session (model recorded in docs/implementer-log.md)

crates/bxctl/src/memory.rs

@@ -98,14 +98,15 @@ fn grouped(n: u64) -> String {
 
 /// Ask `memoryd` and print its answer. `Err` is the line for stderr.
 pub fn run(socket: &Path, ask: &Ask, timeout: Duration, out: &mut dyn Write) -> Result<(), String> {
-    let mut stream = UnixStream::connect(socket)
-        .map_err(|e| format!("cannot reach memoryd at {}: {e}", socket.display()))?;
+    let unreachable =
+        |e: &dyn std::fmt::Display| format!("cannot reach memoryd at {}: {e}", socket.display());
+    let mut stream = UnixStream::connect(socket).map_err(|e| unreachable(&e))?;
     stream
         .set_read_timeout(Some(timeout))
-        .map_err(|e| format!("cannot reach memoryd at {}: {e}", socket.display()))?;
+        .map_err(|e| unreachable(&e))?;
     stream
         .set_write_timeout(Some(timeout))
-        .map_err(|e| format!("cannot reach memoryd at {}: {e}", socket.display()))?;
+        .map_err(|e| unreachable(&e))?;
 
     let msg = match ask {
         Ask::Reindex => Message::Reindex(Empty {}),
@@ -120,8 +121,7 @@ pub fn run(socket: &Path, ask: &Ask, timeout: Duration, out: &mut dyn Write) ->
         r#final: true,
         msg,
     };
-    write_frame(&mut stream, &env)
-        .map_err(|e| format!("cannot reach memoryd at {}: {e}", socket.display()))?;
+    write_frame(&mut stream, &env).map_err(|e| unreachable(&e))?;
 
     let reply = read_frame(&mut stream).map_err(|e| format!("memoryd did not answer: {e}"))?;
     let text = match reply.msg {