Task 1: Simplify Capability; extend BoundEntity

- Make href Optional[str] = None for pattern capabilities
- Remove observe field (v2 architecture observes all hrefs)
- Add rt_filter, match_fn, key_fn fields to Capability
- Add entities default value tuple[()] to Capability
- Add key_override field to BoundEntity
- Update _key() to use key_override when present
- Update _make_observe_paths() to observe all unique hrefs (OBSERVE as accelerator)
- Guard _build() to skip pattern capabilities (href is None)
- Add test_bound_entity_key_override_takes_precedence test
- Update test_capability_defaults to remove observe assertion

All 61 tests passing (60 existing + 1 new).

samsung_appliance/registry/adapter.py

@@ -27,7 +27,7 @@ def _segs(href: str) -> list[str]:
 
 
 def _key(b: BoundEntity) -> str:
-    return f"{b.desc.key}{b.instance}"
+    return f"{b.key_override or b.desc.key}{b.instance}"
 
 
 def _encode(cfg: dict) -> bytes:
@@ -70,7 +70,7 @@ def _make_flatten(bound: list[BoundEntity]) -> Callable[[dict], dict]:
 def _make_observe_paths(bound: list[BoundEntity]) -> list[list[str]]:
     seen, out = set(), []
     for b in bound:
-        if not b.capability.observe or b.href in seen:
+        if b.href in seen:
             continue
         seen.add(b.href)
         out.append(_segs(b.href))

samsung_appliance/registry/capability.py

@@ -9,10 +9,12 @@ from .entities import SamsungEntityDescription
 
 @dataclass(frozen=True, kw_only=True)
 class Capability:
-    href: str
-    entities: tuple[SamsungEntityDescription, ...]
+    href: Optional[str] = None
+    entities: tuple[SamsungEntityDescription, ...] = ()
     poll_tier: str = 'warm'                  # 'hot' | 'warm' | 'cold'
-    observe: bool = True
+    rt_filter: Optional[str] = None          # bind only if rt_filter in rep.get('rt', ())
+    match_fn: Optional[Callable[[dict, dict], bool]] = None  # match_fn(rep, resources) -> bool
+    key_fn: Optional[Callable[[str], str]] = None            # href -> entity key (pattern caps)
     # Rare optional hooks — only operational-state-style resources use these.
     active_when: Optional[Callable[[dict], bool]] = None
     on_observation: Optional[Callable[[dict, dict], None]] = None

samsung_appliance/registry/discovery.py

@@ -19,6 +19,7 @@ class BoundEntity:
     capability: Capability
     desc: SamsungEntityDescription
     instance: str = ''
+    key_override: Optional[str] = None
 
 
 def instance_suffix(href: str) -> str:

samsung_appliance/registry/registry.py

@@ -10,9 +10,14 @@ from .capability import Capability
 
 
 def _build() -> dict[str, Capability]:
-    """Build the registry, raising ValueError if any href is duplicated."""
+    """Build the registry, raising ValueError if any href is duplicated.
+
+    Skips capabilities with href=None (pattern capabilities, handled elsewhere).
+    """
     out: dict[str, Capability] = {}
     for cap in ALL:
+        if cap.href is None:
+            continue
         if cap.href in out:
             raise ValueError(f"duplicate capability href: {cap.href}")
         out[cap.href] = cap

tests/test_adapter.py

@@ -57,3 +57,31 @@ def test_switch_discovery_config_has_correct_payloads(dishwasher_resources):
     assert cfg['state_off'] == 'Off'
     assert 'On' in cfg['value_template']
     assert 'Off' in cfg['value_template']
+
+
+def test_bound_entity_key_override_takes_precedence():
+    from samsung_appliance.registry.adapter import _key
+    from samsung_appliance.registry.discovery import BoundEntity
+    from samsung_appliance.registry.entities import SensorDesc
+
+    cap = common.ENERGY_METER
+    desc = SensorDesc(
+        key='power_watts',
+        field='x.com.samsung.da.power',
+        unit='W',
+        device_class='power',
+        state_class='measurement',
+        value_fn=lambda x: x,
+    )
+
+    # Without key_override, should use desc.key
+    b1 = BoundEntity(href='/power/vs/0', capability=cap, desc=desc, instance='')
+    assert _key(b1) == 'power_watts'
+
+    # With key_override, should use key_override
+    b2 = BoundEntity(href='/power/vs/0', capability=cap, desc=desc, instance='', key_override='foo')
+    assert _key(b2) == 'foo'
+
+    # key_override with instance suffix should preserve instance suffix
+    b3 = BoundEntity(href='/power/vs/0', capability=cap, desc=desc, instance='_1', key_override='bar')
+    assert _key(b3) == 'bar_1'

tests/test_capability.py

@@ -6,7 +6,6 @@ def test_capability_defaults():
     c = Capability(href='/kidslock/vs/0',
                    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