feat: scaffold codespace backend

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

pkg/logger/logger.go

@@ -0,0 +1,11 @@
+package logger
+
+import (
+	"log"
+	"os"
+)
+
+// New returns a standard library logger writing to stdout with a codespace prefix.
+func New() *log.Logger {
+	return log.New(os.Stdout, "codespace ", log.LstdFlags|log.Lshortfile)
+}