diag(qconnect): add decode-layer logging to find envelope unwrap issue

Log whether QCloudInnerEnvelope decode succeeds/fails, message byte
count, and whether queue/renderer decoders succeed or error.

crates/qconnect-transport-ws/Cargo.toml

@@ -14,3 +14,4 @@ thiserror = { workspace = true }
 futures-util = { workspace = true }
 tokio-tungstenite = { version = "0.24", features = ["rustls-tls-webpki-roots"] }
 prost = "0.13"
+log = "0.4"

crates/qconnect-transport-ws/src/transport.rs

@@ -600,17 +600,43 @@ fn handle_incoming_binary(
             //   field 3 (bytes): the actual QConnectMessage protobuf
             // We must unwrap field 3 before passing to the decoders.
             let qconnect_bytes = match QCloudInnerEnvelope::decode(inner_payload.as_slice()) {
-                Ok(envelope) => envelope.message.unwrap_or_default(),
-                Err(_) => inner_payload,
+                Ok(envelope) => {
+                    let msg = envelope.message.unwrap_or_default();
+                    log::info!(
+                        "[QConnect/Decode] Envelope unwrapped: corr={:?} seq={:?} message_len={}",
+                        envelope.correlation_id,
+                        envelope.sequence,
+                        msg.len()
+                    );
+                    msg
+                }
+                Err(err) => {
+                    log::warn!(
+                        "[QConnect/Decode] Envelope decode failed ({}), using raw {} bytes",
+                        err,
+                        inner_payload.len()
+                    );
+                    inner_payload
+                }
             };
 
-            if let Ok(events) = decode_queue_server_events(&qconnect_bytes) {
+            match decode_queue_server_events(&qconnect_bytes) {
+                Ok(events) => {
+                    log::info!("[QConnect/Decode] Queue events decoded: {}", events.len());
                     for event in events {
                         emit(events_tx, TransportEvent::InboundQueueServerEvent(event));
                     }
                 }
+                Err(err) => {
+                    log::warn!("[QConnect/Decode] Queue events decode error: {}", err);
+                }
+            }
 
-            if let Ok(commands) = decode_renderer_server_commands(&qconnect_bytes) {
+            match decode_renderer_server_commands(&qconnect_bytes) {
+                Ok(commands) => {
+                    if !commands.is_empty() {
+                        log::info!("[QConnect/Decode] Renderer commands decoded: {}", commands.len());
+                    }
                     for command in commands {
                         emit(
                             events_tx,
@@ -618,6 +644,10 @@ fn handle_incoming_binary(
                         );
                     }
                 }
+                Err(err) => {
+                    log::debug!("[QConnect/Decode] Renderer commands decode error: {}", err);
+                }
+            }
 
             if let Ok(inbound) = decode_inbound_json(&qconnect_bytes) {
                 emit(events_tx, TransportEvent::InboundReceived(inbound));