feat: add site prefix column to device and rack tables

- derive prefix from the first word of the site name
- display prefix as the first data column
- support NetBox 4.6.5 through 4.6.x
- add packaging, installation documentation, and tests

tests/test_tables.py

@@ -0,0 +1,32 @@
+import ast
+from pathlib import Path
+
+
+MODULE = Path(__file__).parents[1] / "netbox_site_prefix" / "tables.py"
+
+
+def _load_first_word():
+    """Load the pure helper without requiring a local NetBox installation."""
+    module = ast.parse(MODULE.read_text(encoding="utf-8"))
+    function = next(
+        node for node in module.body
+        if isinstance(node, ast.FunctionDef) and node.name == "first_word"
+    )
+    namespace = {}
+    exec(compile(ast.Module(body=[function], type_ignores=[]), str(MODULE), "exec"), namespace)
+    return namespace["first_word"]
+
+
+def test_first_word():
+    first_word = _load_first_word()
+
+    assert first_word("Berlin Campus West") == "Berlin"
+    assert first_word("  DC01\tFrankfurt ") == "DC01"
+
+
+def test_first_word_handles_missing_or_blank_value():
+    first_word = _load_first_word()
+
+    assert first_word(None) is None
+    assert first_word("   ") is None
+