feat(right_arm): /home, /custom_pose, PUT /custom_pose, PUT /offset + fixture conftest

tests/conftest.py

@@ -7,3 +7,29 @@ from pathlib import Path
 _SRC = Path(__file__).resolve().parent.parent / "src"
 if str(_SRC) not in sys.path:
     sys.path.insert(0, str(_SRC))
+
+import pytest
+
+_CFG_PATH = Path(__file__).resolve().parent.parent / "config.yaml"
+
+
+@pytest.fixture(autouse=True)
+def _restore_config_yaml():
+    """Snapshot/restore config.yaml + in-memory singleton.
+    Any test that triggers update_config() would otherwise leave the file
+    cosmetically reformatted (compact flow-style -> block-style) AND/OR
+    semantically mutated. This fixture keeps the working tree clean."""
+    if not _CFG_PATH.exists():
+        yield
+        return
+    snapshot = _CFG_PATH.read_bytes()
+    try:
+        yield
+    finally:
+        _CFG_PATH.write_bytes(snapshot)
+        # Reset in-memory singleton so subsequent tests re-read disk
+        try:
+            from presa_mano import config as _cfg_mod
+            _cfg_mod._STATE["config"] = None  # type: ignore[attr-defined]
+        except Exception:
+            pass  # if internals change, we still get the disk reset