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/phrasebook/lang.go

@@ -0,0 +1,22 @@
+package phrasebook
+
+import (
+	"embed"
+	"io/fs"
+)
+
+//go:embed lang
+var systemLangFS embed.FS
+
+//go:embed backend/lang
+var backendLangFS embed.FS
+
+// backendLang is the framework admin string tree (D-20), laid out as
+// lang/<locale>/lang.yaml so its keys resolve as backend::lang.<group>.<key>.
+func backendLang() fs.FS {
+	sub, err := fs.Sub(backendLangFS, "backend")
+	if err != nil {
+		panic(err)
+	}
+	return sub
+}