lcameraDev: add resolve-only deviceSelector API and deduplicate resolve paths.

Export lcameraDev_resolveDeviceSelectorCReq for attach-identity consumers,
factor live-camera snapshot helpers, and share resolveDeviceSelectorAgainstRecords
with get-or-create session acquisition.

Co-authored-by: Cursor <cursoragent@cursor.com>

commonLibs/lcameraDev/selectorResolve.h

@@ -12,6 +12,10 @@ CameraIdentityRecord resolveSelectorAgainstRecords(
 	const std::vector<SelectorCriterion>& criteria,
 	const std::vector<CameraIdentityRecord>& records);
 
+CameraIdentityRecord resolveDeviceSelectorAgainstRecords(
+	const std::string& deviceSelector,
+	const std::vector<CameraIdentityRecord>& records);
+
 std::string formatCameraListForDiagnostics(
 	const std::vector<CameraIdentityRecord>& records);