distinguish connection failure from empty channel list

query_one_daemon returns Option — None means connection failed,
Some(vec![]) means connected but no channels yet. Fixes telegram
showing as disconnected when it's running but has no messages.

Co-Developed-By: Kent Overstreet <kent.overstreet@linux.dev>

src/thalamus/channels.rs

@@ -305,10 +305,11 @@ async fn subscribe_one_daemon(
 // ── One-shot queries ────────────────────────────────────────────
 
 /// One-shot query: connect to a daemon socket, call list(), return results.
-async fn query_one_daemon(sock: &std::path::Path) -> Vec<(String, bool, u32)> {
+/// Returns None if connection failed, Some(vec) if connected (possibly empty).
+async fn query_one_daemon(sock: &std::path::Path) -> Option<Vec<(String, bool, u32)>> {
     let stream = match UnixStream::connect(sock).await {
         Ok(s) => s,
-        Err(_) => return Vec::new(),
+        Err(_) => return None,
     };
     let (reader, writer) = stream.compat().split();
     let rpc_network = Box::new(twoparty::VatNetwork::new(
@@ -343,7 +344,7 @@ async fn query_one_daemon(sock: &std::path::Path) -> Vec<(String, bool, u32)> {
     }
 
     rpc_handle.abort();
-    result
+    Some(result)
 }
 
 /// Fetch channel status from all daemon sockets.
@@ -387,13 +388,19 @@ async fn fetch_all_channels_inner() -> Vec<(String, bool, u32)> {
             continue;
         }
         let sock = channels_dir.join(format!("{}.sock", daemon_name));
-        let channels = query_one_daemon(&sock).await;
-        if channels.is_empty() {
-            // Daemon is running but has no channels yet (e.g. telegram with no messages)
+        match query_one_daemon(&sock).await {
+            None => {
+                // Connection failed despite socket existing
+                result.push((daemon_name, false, 0));
+            }
+            Some(channels) if channels.is_empty() => {
+                // Connected but no channels yet
                 result.push((daemon_name, true, 0));
-        } else {
+            }
+            Some(channels) => {
                 result.extend(channels);
             }
         }
+    }
     result
 }