Improve commits list performance to reduce unnecessary database queries (#33528)

When listing commits, Gitea attempts to retrieve the actual user based
on the commit email. Querying users one by one from the database is
inefficient. This PR optimizes the process by batch querying users by
email, reducing the number of database queries.

tests/integration/repo_commits_test.go

@@ -12,11 +12,14 @@ import (
 	"testing"
 
 	auth_model "code.gitea.io/gitea/models/auth"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/json"
 	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/tests"
 
+	"github.com/PuerkitoBio/goquery"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -35,6 +38,44 @@ func TestRepoCommits(t *testing.T) {
 	assert.NotEmpty(t, commitURL)
 }
 
+func Test_ReposGitCommitListNotMaster(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+	// Login as User2.
+	session := loginUser(t, user.Name)
+
+	// Test getting commits (Page 1)
+	req := NewRequestf(t, "GET", "/%s/repo16/commits/branch/master", user.Name)
+	resp := session.MakeRequest(t, req, http.StatusOK)
+
+	doc := NewHTMLParser(t, resp.Body)
+	commits := []string{}
+	doc.doc.Find("#commits-table .commit-id-short").Each(func(i int, s *goquery.Selection) {
+		commitURL, exists := s.Attr("href")
+		assert.True(t, exists)
+		assert.NotEmpty(t, commitURL)
+		commits = append(commits, path.Base(commitURL))
+	})
+
+	assert.Len(t, commits, 3)
+	assert.EqualValues(t, "69554a64c1e6030f051e5c3f94bfbd773cd6a324", commits[0])
+	assert.EqualValues(t, "27566bd5738fc8b4e3fef3c5e72cce608537bd95", commits[1])
+	assert.EqualValues(t, "5099b81332712fe655e34e8dd63574f503f61811", commits[2])
+
+	userNames := []string{}
+	doc.doc.Find("#commits-table .author-wrapper").Each(func(i int, s *goquery.Selection) {
+		userPath, exists := s.Attr("href")
+		assert.True(t, exists)
+		assert.NotEmpty(t, userPath)
+		userNames = append(userNames, path.Base(userPath))
+	})
+
+	assert.Len(t, userNames, 3)
+	assert.EqualValues(t, "User2", userNames[0])
+	assert.EqualValues(t, "user21", userNames[1])
+	assert.EqualValues(t, "User2", userNames[2])
+}
+
 func doTestRepoCommitWithStatus(t *testing.T, state string, classes ...string) {
 	defer tests.PrepareTestEnv(t)()