refactor(module): simplify module name to Wavelet and standardize import paths

- Declared module Wavelet in backend/go.mod
- Replaced github.com/Rain-kl/Wavelet/ with clean Wavelet/ import paths across backend codebase
- Updated architecture guards, Makefile, swagger, and build tests
- 100% passed all tests, lint checks, and binary compilation

backend/cmd/all.go

@@ -1,4 +1,3 @@
-// Copyright 2025 linux.do
 // Copyright 2026 Arctel.net
 // SPDX-License-Identifier: Apache-2.0
 
@@ -8,7 +7,7 @@ package cmd
 import (
 	"log"
 
-	"github.com/Rain-kl/Wavelet/core"
+	"Wavelet/core"
 	"github.com/spf13/cobra"
 )