fix(tui): realtime ETA updates during phase 3 cluster restore

Previously, the ETA during phase 3 (database restores) would appear to
hang because dbPhaseElapsed was only updated when a new database started
restoring, not during the restore operation itself.

Fixed by:
- Added phase3StartTime to track when phase 3 begins
- Calculate dbPhaseElapsed in realtime using time.Since(phase3StartTime)
- ETA now updates every 100ms tick instead of only on database transitions

This ensures the elapsed time and ETA display continuously update during
long-running database restores.

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**: 2026-01-18_11:39:42_UTC
-- **Git Commit**: 59a717a
+- **Build Time**: 2026-01-18_17:17:17_UTC
+- **Git Commit**: a0a401c
 
 ## Recent Updates (v1.1.0)
 - ✅ Fixed TUI progress display with line-by-line output