bxctl: escape frame errors; say the outcome is unknown after a timeout

From the independent review of task 23. serde quotes a bad frame's text after
decoding, so a compromised peer could put escape sequences in it. A timed-out
admin request now says whether brokerd acted is unknown, since it may have.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

crates/bxctl/src/admin.rs

@@ -40,7 +40,17 @@ pub fn request_with_timeout(
         msg,
     };
     write_frame(&mut stream, &env).map_err(AdminError::Frame)?;
-    let answer = read_frame(&mut stream).map_err(AdminError::Frame)?;
+    let answer = read_frame(&mut stream).map_err(|e| match e {
+        FrameError::Io(io)
+            if matches!(
+                io.kind(),
+                io::ErrorKind::WouldBlock | io::ErrorKind::TimedOut
+            ) =>
+        {
+            AdminError::NoAnswer(timeout)
+        }
+        other => AdminError::Frame(other),
+    })?;
     if answer.id != 1 || !answer.r#final {
         return Err(AdminError::Protocol(
             "expected an answer for request 1".to_string(),
@@ -70,19 +80,27 @@ pub enum AdminError {
     Protocol(String),
     /// Writing the output failed; the caller stops rather than write again.
     Io(std::io::Error),
+    /// The request was sent and no answer came in time, so what brokerd did is not known.
+    NoAnswer(std::time::Duration),
 }
 
 impl std::fmt::Display for AdminError {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
             AdminError::Connect(p, e) => write!(f, "cannot reach brokerd at {}: {e}", p.display()),
-            AdminError::Frame(e) => write!(f, "{e}"),
+            // serde quotes the offending text of a bad frame, decoded: escape it.
+            AdminError::Frame(e) => write!(f, "{}", escape_json_text(&e.to_string())),
             // The detail may carry text from the inference server or a tool: escape it.
             AdminError::Refused(w) => {
                 write!(f, "{}: {}", code_name(w.code), escape_json_text(&w.detail))
             }
             AdminError::Protocol(s) => write!(f, "{s}"),
             AdminError::Io(e) => write!(f, "{e}"),
+            AdminError::NoAnswer(t) => write!(
+                f,
+                "brokerd did not answer within {} s; whether it acted is unknown: check `bxctl approvals` and `bxctl audit verify`",
+                t.as_secs_f64()
+            ),
         }
     }
 }

crates/bxctl/src/chat.rs

@@ -24,7 +24,8 @@ impl std::fmt::Display for ChatError {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
             ChatError::Connect(e) => write!(f, "{e}"),
-            ChatError::Frame(e) => write!(f, "{e}"),
+            // serde quotes the offending text of a bad frame, decoded: escape it.
+            ChatError::Frame(e) => write!(f, "{}", escape_json_text(&e.to_string())),
             // The detail may carry the inference server's body: escape it like model text.
             ChatError::Refused(w) => {
                 write!(f, "{}: {}", code_name(w.code), escape_json_text(&w.detail))