fix: release rgb_send_lock on all channel open failure paths

Three targeted fixes in the LDK event handlers:

- FundingGenerationReady: release lock unconditionally after
  funding_transaction_generated(), not just on error.  Once the funding
  TX is handed to LDK the RGB wallet operations are complete.
- ChannelPending: release lock before spawn_blocking so it is freed
  even if the subsequent rgb_send_end task panics.
- ChannelClosed: release lock when channel_funding_txo is None
  (channel closed during negotiation, before any funding was created).

Ref: #111

Author: bitwalt

src/ldk.rs

@@ -690,8 +690,8 @@ async fn handle_ldk_events(
             {
                 tracing::error!(
                         "ERROR: Channel went away before we could fund it. The peer disconnected or refused the channel.");
-                *unlocked_state.rgb_send_lock.lock().unwrap() = false;
             }
+            *unlocked_state.rgb_send_lock.lock().unwrap() = false;
         }
         Event::FundingTxBroadcastSafe { .. } => {
             // We don't use the manual broadcasting feature, so this event should never be seen.
@@ -1055,6 +1055,8 @@ async fn handle_ldk_events(
                     is_channel_rgb(&channel_id, &PathBuf::from(&static_state.ldk_data_dir));
                 tracing::info!("Initiator of the channel (colored: {})", is_chan_colored);
 
+                *unlocked_state.rgb_send_lock.lock().unwrap() = false;
+
                 let _txid = tokio::task::spawn_blocking(move || {
                     if is_chan_colored {
                         state_copy.rgb_send_end(psbt_str_copy).map(|r| r.txid)
@@ -1068,8 +1070,6 @@ async fn handle_ldk_events(
                     tracing::error!("Error completing channel opening: {e:?}");
                     ReplayEvent()
                 })?;
-
-                *unlocked_state.rgb_send_lock.lock().unwrap() = false;
             } else {
                 // acceptor
                 let consignment_path = static_state
@@ -1115,7 +1115,7 @@ async fn handle_ldk_events(
             user_channel_id: _,
             counterparty_node_id,
             channel_capacity_sats: _,
-            channel_funding_txo: _,
+            channel_funding_txo,
             last_local_balance_msat: _,
         } => {
             tracing::info!(
@@ -1127,6 +1127,10 @@ async fn handle_ldk_events(
                 reason
             );
 
+            if channel_funding_txo.is_none() {
+                *unlocked_state.rgb_send_lock.lock().unwrap() = false;
+            }
+
             unlocked_state.delete_channel_id(channel_id);
         }
         Event::DiscardFunding { channel_id, .. } => {