fix: resolve isort/black/pylint lint failures

- Remove extra blank line after imports in test_versioning.py (isort)
- Black-format all 4 changed files
- Rename unused _validate_external sku param to _sku (pylint W0613)
- Add pylint: disable=invalid-name for intentional _v1/_v2 class suffixes
- Achieves 10.00/10 pylint score on changed lib files

Author: Cataldir

lib/src/holiday_peak_lib/agents/guardrails/enrichment_guardrail.py

@@ -190,9 +190,7 @@ class SourceRef:
     source_system: str
     source_id: str
     confidence: float = 1.0
-    retrieved_at: str = field(
-        default_factory=lambda: datetime.now(tz=timezone.utc).isoformat()
-    )
+    retrieved_at: str = field(default_factory=lambda: datetime.now(tz=timezone.utc).isoformat())
 
     def as_tag(self) -> str:
         """Return a compact string tag suitable for embedding in content metadata."""
@@ -256,7 +254,7 @@ async def validate(
 
         return refs if refs else None
 
-    async def _validate_external(self, sku: str) -> list[SourceRef]:  # noqa: ARG002
+    async def _validate_external(self, _sku: str) -> list[SourceRef]:
         """Hook for subclasses to add cross-service source validation.
 
         Default implementation returns an empty list (no external check).

lib/src/holiday_peak_lib/connectors/common/versioning.py

@@ -207,7 +207,7 @@ class BaseConnectorProtocol(ABC, metaclass=_ProtocolMeta):
 # ---------------------------------------------------------------------------
 
 
-class PIMConnectorProtocol_v1(BaseConnectorProtocol):
+class PIMConnectorProtocol_v1(BaseConnectorProtocol):  # pylint: disable=invalid-name
     """PIM connector protocol v1 — baseline product data operations.
 
     Provides fundamental read operations against any product information
@@ -248,7 +248,7 @@ async def list_products(
 # ---------------------------------------------------------------------------
 
 
-class PIMConnectorProtocol_v2(PIMConnectorProtocol_v1):
+class PIMConnectorProtocol_v2(PIMConnectorProtocol_v1):  # pylint: disable=invalid-name
     """PIM connector protocol v2 — adds lifecycle, variants, and keyword search.
 
     v2 is backward-compatible with v1 (same major version).  All v1 methods
@@ -480,11 +480,7 @@ def _apply_version_mask(self, data: dict[str, Any]) -> dict[str, Any]:
 
         known_at_client = self._fields_for_version(self._client_version)
         all_protocol = self._all_protocol_fields()
-        return {
-            k: v
-            for k, v in data.items()
-            if k in known_at_client or k not in all_protocol
-        }
+        return {k: v for k, v in data.items() if k in known_at_client or k not in all_protocol}
 
     # ------------------------------------------------------------------
     # Core PIM method delegates with version masking
@@ -540,19 +536,13 @@ def diff_protocols(
     """
     for arg, label in ((from_version, "from_version"), (to_version, "to_version")):
         if not (isinstance(arg, type) and issubclass(arg, BaseConnectorProtocol)):
-            raise TypeError(
-                f"{label} must be a BaseConnectorProtocol subclass, got {arg!r}"
-            )
+            raise TypeError(f"{label} must be a BaseConnectorProtocol subclass, got {arg!r}")
 
     from_fields = {f.name: f for f in getattr(from_version, "FIELDS", [])}
     to_fields = {f.name: f for f in getattr(to_version, "FIELDS", [])}
 
     added = [name for name in to_fields if name not in from_fields]
     removed = [name for name in from_fields if name not in to_fields]
-    deprecated = [
-        name
-        for name, f in to_fields.items()
-        if f.deprecated and name not in removed
-    ]
+    deprecated = [name for name, f in to_fields.items() if f.deprecated and name not in removed]
 
     return ProtocolDiff(added=added, removed=removed, deprecated=deprecated)

lib/tests/test_connectors/test_versioning.py

@@ -18,7 +18,6 @@
     register_protocol,
 )
 
-
 # ---------------------------------------------------------------------------
 # Helpers / fixtures
 # ---------------------------------------------------------------------------
@@ -300,6 +299,7 @@ async def test_unknown_keys_are_preserved(self, connector):
             protocol_class=PIMConnectorProtocol_v2,
             client_version=ProtocolVersion(1, 0),
         )
+
         # Monkey-patch connector to return an internal key
         async def patched_get(product_id: str) -> dict[str, Any]:
             data = await ConcretePIMv2().get_product(product_id)