feat: add Capability dataclass

tests/test_capability.py

@@ -0,0 +1,20 @@
+from samsung_appliance.registry.capability import Capability
+from samsung_appliance.registry.entities import BinarySensorDesc
+
+
+def test_capability_defaults():
+    c = Capability(rt='x.com.samsung.da.kidsLock',
+                   entities=(BinarySensorDesc(key='child_lock', field='x.com.samsung.da.kidsLock'),))
+    assert c.poll_tier == 'warm'
+    assert c.observe is True
+    assert c.active_when is None
+    assert len(c.entities) == 1
+
+
+def test_capability_is_frozen():
+    c = Capability(rt='x', entities=())
+    try:
+        c.rt = 'y'
+    except Exception:
+        return
+    raise AssertionError("expected frozen dataclass")