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/plugins/domain/upload/util/media.go

@@ -6,7 +6,7 @@ package util
 import (
 	"strings"
 
-	"github.com/Rain-kl/Wavelet/plugins/domain/upload/shared"
+	"Wavelet/plugins/domain/upload/shared"
 )
 
 // IsImageExtension reports whether ext is a common image format.

backend/plugins/domain/upload/util/utils.go

@@ -1,4 +1,3 @@
-// Copyright 2025 linux.do
 // Copyright 2026 Arctel.net
 // SPDX-License-Identifier: Apache-2.0
 
@@ -16,7 +15,7 @@ import (
 	"io"
 	"strings"
 
-	"github.com/Rain-kl/Wavelet/plugins/domain/upload/shared"
+	"Wavelet/plugins/domain/upload/shared"
 	"github.com/deepteams/webp"
 	_ "golang.org/x/image/webp" // Register WebP decoder for image.Decode
 )