chore: schema rápido en CLAUDE.md, sync Metabase en CLI, fix main.py

Agrega documentación de schema rápido en CLAUDE.md, regla sources en INDEX.
CLI fn index sincroniza registry.db a directorio Metabase si existe.
fn show muestra campos source_*. Fix import en metabase_registry/main.py.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cmd/fn/main.go

@@ -105,6 +105,18 @@ func cmdIndex() {
 	// Flush WAL to main db file so external readers (e.g. Metabase) see changes.
 	db.WalCheckpoint()
 
+	// Sync registry.db to Metabase mount directory if it exists.
+	metabaseCopy := filepath.Join(r, ".metabase-registry", "registry.db")
+	if _, err := os.Stat(filepath.Dir(metabaseCopy)); err == nil {
+		src := filepath.Join(r, dbName)
+		data, err := os.ReadFile(src)
+		if err == nil {
+			if err := os.WriteFile(metabaseCopy, data, 0666); err != nil {
+				fmt.Fprintf(os.Stderr, "warning: could not sync to metabase: %v\n", err)
+			}
+		}
+	}
+
 	fmt.Printf("Indexed %d functions, %d types, %d apps\n", result.Functions, result.Types, result.Apps)
 	for _, e := range result.ValidationErrors {
 		fmt.Fprintf(os.Stderr, "  INVALID: %s\n", e)
@@ -341,6 +353,11 @@ func printFunction(f *registry.Function) {
 	if f.Code != "" {
 		fmt.Printf("\nCode:\n%s\n", f.Code)
 	}
+	if f.SourceRepo != "" {
+		fmt.Printf("Source repo: %s\n", f.SourceRepo)
+		fmt.Printf("Source license: %s\n", f.SourceLicense)
+		fmt.Printf("Source file: %s\n", f.SourceFile)
+	}
 	if f.Kind == registry.KindComponent {
 		fmt.Printf("Framework:   %s\n", f.Framework)
 		if f.HasState != nil {
@@ -365,6 +382,11 @@ func printType(t *registry.Type) {
 	if len(t.UsesTypes) > 0 {
 		fmt.Printf("Uses types:  %s\n", strings.Join(t.UsesTypes, ", "))
 	}
+	if t.SourceRepo != "" {
+		fmt.Printf("Source repo: %s\n", t.SourceRepo)
+		fmt.Printf("Source license: %s\n", t.SourceLicense)
+		fmt.Printf("Source file: %s\n", t.SourceFile)
+	}
 	if t.Definition != "" {
 		fmt.Printf("\nDefinition:\n%s\n", t.Definition)
 	}