Make shared prompt filesystem composition generic

internal/modules/sharedassets/assets.go

@@ -9,10 +9,28 @@ import (
 //go:embed assets/prompts/*.md
 var embeddedAssets embed.FS
 
+var commonDNDPromptFiles = []string{
+	"common-dnd-system.md",
+	"common-dnd-transcript.md",
+	"common-dnd-references.md",
+}
+
 func Register(registry *llm.AssetRegistry) error {
 	return registry.RegisterPromptFS(embeddedAssets, "assets/prompts")
 }
 
+func SharedPromptFiles() []SharedPromptFile {
+	files := make([]SharedPromptFile, 0, len(commonDNDPromptFiles))
+	for _, name := range commonDNDPromptFiles {
+		files = append(files, SharedPromptFile{
+			Name: name,
+			FS:   embeddedAssets,
+			Path: "assets/prompts/" + name,
+		})
+	}
+	return files
+}
+
 func CommonHashParts() []llm.AssetHashPart {
 	return []llm.AssetHashPart{
 		{FS: embeddedAssets, Path: "assets/prompts/common-dnd-system.md"},