Enhance hosts file serialization and entry formatting for proper tab alignment; update tests to reflect changes.

tests/test_models.py

@@ -67,7 +67,7 @@ class TestHostEntry:
             comment="Loopback"
         )
         line = entry.to_hosts_line()
-        assert line == "127.0.0.1 localhost local # Loopback"
+        assert line == "127.0.0.1\tlocalhost\tlocal\t# Loopback"
     
     def test_to_hosts_line_inactive(self):
         """Test conversion to hosts file line format for inactive entry."""
@@ -77,7 +77,7 @@ class TestHostEntry:
             is_active=False
         )
         line = entry.to_hosts_line()
-        assert line == "# 192.168.1.1 router"
+        assert line == "# 192.168.1.1\trouter"
     
     def test_from_hosts_line_simple(self):
         """Test parsing simple hosts file line."""