refactor: migrate from zerolog to zap logging library

Replace github.com/rs/zerolog with go.uber.org/zap throughout the codebase
to improve performance and provide better structured logging capabilities.

Key changes:
- Replace zerolog imports with zap and zapcore
- Implement custom Logger wrapper in log.go to maintain zerolog-like API
- Add LogEvent struct with chained methods (Str, Int, Err, Bool, etc.)
- Update all logging calls to use the new zap-based wrapper
- Replace JSON encoders with Console encoders for better readability

Benefits:
- Better performance with zap's optimized logging
- Consistent structured logging across all components
- Maintained zerolog-like API for easy migration
- Proper field context preservation for debugging
- Multi-core logging architecture for better output control

All tests pass and build succeeds.

cmd/cli/commands.go

@@ -270,7 +270,7 @@ NOTE: running "ctrld start" without any arguments will start already installed c
 								_, _ = patchNetIfaceName(iff)
 								name = iff.Name
 							}
-							logger := mainLog.Load().With().Str("iface", name).Logger()
+							logger := mainLog.Load().With().Str("iface", name)
 							logger.Debug().Msg("setting DNS successfully")
 							if res.All {
 								// Log that DNS is set for other interfaces.