refactor: make git package handle all git operations (#38543)

before: gitrepo vs git packages
after: git package fully handle all git operations

by the way, use `WithRepo(repo)` instead of `WithDir(repo.Path)` to hide
path details.

benefits:

1. remove all unnecessary wrappers, developers no need to struggle with
"which package should be used"
2. simplify code, RepositoryFacade can (will) be used everywhere, all
"path" details are (will be) hidden

services/repository/gitgraph/graph.go

@@ -14,7 +14,7 @@ import (
 )
 
 // GetCommitGraph return a list of commit (GraphItems) from all branches
-func GetCommitGraph(ctx context.Context, r *git.Repository, page, maxAllowedColors int, hidePRRefs bool, branches, files []string) (*Graph, error) {
+func GetCommitGraph(ctx context.Context, gitRepo *git.Repository, page, maxAllowedColors int, hidePRRefs bool, branches, files []string) (*Graph, error) {
 	format := "DATA:%D|%H|%ad|%h|%s"
 
 	if page == 0 {
@@ -48,7 +48,7 @@ func GetCommitGraph(ctx context.Context, r *git.Repository, page, maxAllowedColo
 	stdoutReader, stdoutReaderClose := graphCmd.MakeStdoutPipe()
 	defer stdoutReaderClose()
 	if err := graphCmd.
-		WithDir(r.Path).
+		WithRepo(gitRepo).
 		WithPipelineFunc(func(ctx gitcmd.Context) error {
 			scanner := bufio.NewScanner(stdoutReader)
 			parser := &Parser{}