refactor: split flat core into capability packages, layer the conversations service, English defaults for every model-facing text

tests/test_config_siblings.py

@@ -0,0 +1,16 @@
+import tempfile
+from pathlib import Path
+
+from beaver_gateway import config
+
+
+def test_config_imports_sibling_modules():
+    root = Path(tempfile.mkdtemp(prefix="beaver-cfg-"))
+    (root / "policy_sibling.py").write_text("RULES = ('x',)\n")
+    (root / "config.py").write_text(
+        "from policy_sibling import RULES\n"
+        "assert RULES == ('x',)\n"
+        "gateway = Gateway()\n"
+    )
+    gw = config.load(root / "config.py")
+    assert gw.agents == []