fix: rename manager module to git.zkcoi.com/zkcoi/Meshray-Manager

- go.mod module path matches repo zkcoi/Meshray-Manager (case-distinct from zkcoi/Meshray/core)
- rewrite internal imports meshray/{internal,web,pkg} -> Meshray-Manager/... (core refs kept)
- sync README.md / install.sh repo URLs; add CHANGELOG entry

cmd/testembed/main.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"io/fs"
 
-	"git.zkcoi.com/zkcoi/meshray/web"
+	"git.zkcoi.com/zkcoi/Meshray-Manager/web"
 )
 
 func main() {