refactor: Enhance session management and error handling in AgentService and related components

- Improved session handling by implementing ensureSession to load sessions from disk if not in memory, reducing "session not found" errors.
- Enhanced error messages for non-existent sessions, providing clearer diagnostics.
- Updated CodexProvider and OpencodeProvider to improve error handling and messaging.
- Refactored various routes to use async/await for better readability and error handling.
- Added event emission for merge and stash operations in the MergeService and StashService.
- Cleaned up error messages in AgentExecutor to remove redundant prefixes and ANSI codes for better clarity.

apps/ui/src/components/views/board-view/hooks/use-board-actions.ts

@@ -1151,6 +1151,9 @@ export function useBoardActions({
         if (result.success) {
           // Refresh features from server to sync React Query cache
           loadFeatures();
+          toast.success('All verified features archived', {
+            description: `Archived ${verifiedFeatures.length} feature(s).`,
+          });
         } else {
           logger.error('Bulk archive failed:', result);
           // Reload features to sync state with server
@@ -1162,10 +1165,6 @@ export function useBoardActions({
       // Reload features to sync state with server on error
       loadFeatures();
     }
-
-    toast.success('All verified features archived', {
-      description: `Archived ${verifiedFeatures.length} feature(s).`,
-    });
   }, [features, runningAutoTasks, autoMode, updateFeature, currentProject, loadFeatures]);
 
   const handleDuplicateFeature = useCallback(