fix: cluster restore database detection and TUI error display

- Fixed psql connection for database detection (always use -h flag)
- Use CombinedOutput() to capture stderr for better diagnostics
- Added existingDBError tracking in restore preview
- Show 'Unable to detect' instead of misleading 'None' when listing fails
- Disable cleanup toggle when database detection failed

bin/README.md

@@ -4,8 +4,8 @@ This directory contains pre-compiled binaries for the DB Backup Tool across mult
 
 ## Build Information
 - **Version**: 3.42.50
-- **Build Time**: 2026-01-17_15:15:55_UTC
-- **Git Commit**: 0e050b2
+- **Build Time**: 2026-01-17_15:26:14_UTC
+- **Git Commit**: df1ab2f
 
 ## Recent Updates (v1.1.0)
 - ✅ Fixed TUI progress display with line-by-line output