refactor(10.2-01): nest framework packages under modules

- Move remaining beach packages and embedded admin assets\n- Rewrite framework, example, build, and gate paths

modules/cabana/schema.go

@@ -0,0 +1,58 @@
+package cabana
+
+import (
+	"bytes"
+	"fmt"
+	"io/fs"
+	"path"
+	"strings"
+
+	"github.com/goccy/go-yaml"
+)
+
+func decodeStrict(raw []byte, dest any) error {
+	dec := yaml.NewDecoder(bytes.NewReader(raw), yaml.DisallowUnknownField())
+	if err := dec.Decode(dest); err != nil {
+		return err
+	}
+	return nil
+}
+
+func readAsset(fsys fs.FS, name string) ([]byte, error) {
+	name = path.Clean(name)
+	if name == "." || strings.HasPrefix(name, "..") || strings.Contains(name, "..") {
+		return nil, fmt.Errorf("path escapes the plugin")
+	}
+	return fs.ReadFile(fsys, name)
+}
+
+func assetPath(pluginID, ref string) (string, error) {
+	ref = strings.TrimSpace(ref)
+	ref = strings.TrimPrefix(ref, "~/")
+	prefix := "plugins/" + strings.ReplaceAll(pluginID, ".", "/") + "/"
+	ref = strings.TrimPrefix(ref, prefix)
+	ref = path.Clean(ref)
+	if ref == "." || strings.HasPrefix(ref, "..") || strings.Contains(ref, "..") {
+		return "", fmt.Errorf("list path escapes the plugin")
+	}
+	return ref, nil
+}
+
+func identifier(s string) bool {
+	if s == "" {
+		return false
+	}
+	for i, r := range s {
+		switch {
+		case r >= 'a' && r <= 'z', r >= 'A' && r <= 'Z', r == '_':
+		case i > 0 && r >= '0' && r <= '9':
+		default:
+			return false
+		}
+	}
+	return true
+}
+
+func bootErr(pluginID, controllerID, file string, err error) error {
+	return fmt.Errorf("cabana: admin schema %s/%s/%s: %w", pluginID, controllerID, file, err)
+}