feat: integrate site prefix column from Netbox-Prefixes

Device and rack tables show the first word of the site name as the
first data column. Replaces the separate netbox_site_prefix plugin and
can be disabled with site_prefix_column_enabled.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

netbox_utilities/tests/test_site_prefix.py

@@ -0,0 +1,36 @@
+from types import SimpleNamespace
+
+from django.test import SimpleTestCase
+
+from netbox_utilities.site_prefix import COLUMN_NAME, SitePrefixColumn, first_word, prepend_to_default_columns
+
+
+class SitePrefixTest(SimpleTestCase):
+    def test_first_word(self):
+        self.assertEqual(first_word("Berlin Campus West"), "Berlin")
+        self.assertEqual(first_word("  DC01\tFrankfurt "), "DC01")
+
+    def test_first_word_handles_missing_or_blank_value(self):
+        self.assertIsNone(first_word(None))
+        self.assertIsNone(first_word("   "))
+
+    def test_column_renders_first_word_of_site_name(self):
+        column = SitePrefixColumn()
+
+        self.assertEqual(column.render(SimpleNamespace(name="DC01 Frankfurt")), "DC01")
+        self.assertIsNone(column.render(None))
+
+    def test_prefix_column_is_first_default_column(self):
+        table = SimpleNamespace(Meta=SimpleNamespace(default_columns=("pk", "name", COLUMN_NAME, "status")))
+
+        prepend_to_default_columns(table)
+
+        self.assertEqual(table.Meta.default_columns, ("pk", COLUMN_NAME, "name", "status"))
+
+    def test_device_and_rack_tables_offer_prefix_column(self):
+        from dcim.tables import DeviceTable, RackTable
+
+        self.assertIn(COLUMN_NAME, DeviceTable.base_columns)
+        self.assertIn(COLUMN_NAME, RackTable.base_columns)
+        self.assertEqual(DeviceTable.Meta.default_columns[:2], ("pk", COLUMN_NAME))
+        self.assertEqual(RackTable.Meta.default_columns[:2], ("pk", COLUMN_NAME))