Remove redundant prepared input APIs

internal/artifactpolicy/policy.go

@@ -53,7 +53,6 @@ type Source struct {
 // ScriptoriumInputSourceDescriptor describes one validated Scriptorium input source.
 type ScriptoriumInputSourceDescriptor struct {
 	Source          Source
-	PreparedInput   *PreparedInputSourceDescriptor
 	PreviousSession *PreviousSessionSourceDescriptor
 }
 
@@ -170,8 +169,7 @@ func DescribeScriptoriumInputSource(source string) (ScriptoriumInputSourceDescri
 	}
 	if prepared, ok := DescribePreparedInputSource(trimmed); ok {
 		return ScriptoriumInputSourceDescriptor{
-			Source:        Source{ID: prepared.SourceID, Kind: SourceKindStableInput},
-			PreparedInput: &prepared,
+			Source: Source{ID: prepared.SourceID, Kind: SourceKindStableInput},
 		}, nil
 	}
 	if strings.HasPrefix(trimmed, "narratio.previous_session.artifact") {
@@ -196,13 +194,6 @@ func DescribeScriptoriumInputSource(source string) (ScriptoriumInputSourceDescri
 	return ScriptoriumInputSourceDescriptor{Source: classified}, nil
 }
 
-// IsStableInputSource reports whether source is a prepared stable input source
-// available only to Scriptorium input resolution.
-func IsStableInputSource(source string) bool {
-	_, ok := DescribePreparedInputSource(source)
-	return ok
-}
-
 var preparedInputSources = map[string]PreparedInputSourceDescriptor{
 	SourceInputPlayers: {
 		SourceID:     SourceInputPlayers,