v3.40.0: Restore diagnostics and error reporting

Features:
- restore diagnose command for backup file analysis
- Deep COPY block verification for truncated dump detection
- PGDMP signature and gzip integrity validation
- Detailed error reports with --save-debug-log flag
- Ring buffer stderr capture (prevents OOM on 2M+ errors)
- Error classification with actionable recommendations

TUI Enhancements:
- Automatic dump validity safety check before restore
- Press 'd' in archive browser to diagnose backups
- Press 'd' in restore preview for debug log toggle
- Debug logs saved to /tmp on failure when enabled

Documentation:
- Updated README with diagnose command and examples
- Updated CHANGELOG with full feature list
- Updated restore preview screenshots

build_all.sh

@@ -15,7 +15,7 @@ echo "🔧 Using Go version: $GO_VERSION"
 
 # Configuration
 APP_NAME="dbbackup"
-VERSION="3.2.0"
+VERSION="3.40.0"
 BUILD_TIME=$(date -u '+%Y-%m-%d_%H:%M:%S_UTC')
 GIT_COMMIT=$(git rev-parse --short HEAD 2>/dev/null || echo "unknown")
 BIN_DIR="bin"