Carry installer input-method selection into the target (#237)

* Carry the installer input-method choice into the target

* Support Archinstall 4.5 sanity checks

* Constrain VM keyboard choices to supported credential layouts

* Cover VM keyboard offsets and reject absent choices

test/unit/test_archinstall_sanity.py

@@ -0,0 +1,29 @@
+"""Exercise the compatibility boundary without importing host archinstall."""
+import ast
+from pathlib import Path
+import types
+import unittest
+
+ROOT = Path(__file__).resolve().parents[2]
+source = ROOT / "configs/airootfs/usr/share/omarchy-iso/orchestrator/archinstall_adapter.py"
+tree = ast.parse(source.read_text())
+namespace = {}
+functions = [node for node in tree.body if isinstance(node, ast.FunctionDef) and node.name in {"_method_accepts", "sanity_check"}]
+exec(compile(ast.Module(body=functions, type_ignores=[]), str(source), "exec"), namespace)
+
+
+class SanityCheckTest(unittest.TestCase):
+    def test_legacy_archinstall_stays_offline(self):
+        calls = []
+        def check(offline=False, skip_ntp=False, skip_wkd=False):
+            calls.append((offline, skip_ntp, skip_wkd))
+        namespace["sanity_check"](types.SimpleNamespace(sanity_check=check))
+        self.assertEqual(calls, [(True, True, True)])
+
+    def test_archinstall_45_does_not_receive_removed_argument(self):
+        calls = []
+        class Installer:
+            def sanity_check(self, skip_ntp=False, skip_wkd=False):
+                calls.append((skip_ntp, skip_wkd))
+        namespace["sanity_check"](Installer())
+        self.assertEqual(calls, [(True, True)])