Add generic adapter capability model

dns_sync/interfaces.py

@@ -1,8 +1,28 @@
 from typing import Protocol
 
+from .adapters import (
+    Capability,
+    DiscoveredObject,
+    Endpoint,
+    NormalizedObject,
+    PlanAction,
+)
 from .models import DesiredRecord, ProviderCapabilities, ProviderRecord
 
 
+class AdapterPlugin(Protocol):
+    name: str
+    endpoint: Endpoint
+    capabilities: frozenset[Capability]
+
+    def connect(self) -> None: ...
+    def discover(self, object_type: str) -> list[DiscoveredObject]: ...
+    def apply(self, action: PlanAction) -> str | None: ...
+    def verify(self, object: NormalizedObject) -> bool: ...
+
+
+# Compatibility protocols for the existing DNS-only execution path. They remain
+# in place until the current plugins and CLI are migrated to AdapterPlugin.
 class SourcePlugin(Protocol):
     name: str