Never use /api/v1 from Gitea UI Pages (#19318)

Reusing `/api/v1` from Gitea UI Pages have pros and cons.
Pros:
1) Less code copy

Cons:
1) API/v1 have to support shared session with page requests.
2) You need to consider for each other when you want to change something about api/v1 or page.

This PR moves all dependencies to API/v1 from UI Pages.

Partially replace #16052

integrations/user_test.go

@@ -8,8 +8,11 @@ import (
 	"net/http"
 	"testing"
 
+	"code.gitea.io/gitea/models"
+	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
 	user_model "code.gitea.io/gitea/models/user"
+	api "code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/test"
 	"code.gitea.io/gitea/modules/translation/i18n"
 
@@ -222,3 +225,26 @@ func testExportUserGPGKeys(t *testing.T, user, expected string) {
 	// t.Log(resp.Body.String())
 	assert.Equal(t, expected, resp.Body.String())
 }
+
+func TestListStopWatches(t *testing.T) {
+	defer prepareTestEnv(t)()
+
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1}).(*repo_model.Repository)
+	owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: repo.OwnerID}).(*user_model.User)
+
+	session := loginUser(t, owner.Name)
+	req := NewRequestf(t, "GET", "/user/stopwatches")
+	resp := session.MakeRequest(t, req, http.StatusOK)
+	var apiWatches []*api.StopWatch
+	DecodeJSON(t, resp, &apiWatches)
+	stopwatch := unittest.AssertExistsAndLoadBean(t, &models.Stopwatch{UserID: owner.ID}).(*models.Stopwatch)
+	issue := unittest.AssertExistsAndLoadBean(t, &models.Issue{ID: stopwatch.IssueID}).(*models.Issue)
+	if assert.Len(t, apiWatches, 1) {
+		assert.EqualValues(t, stopwatch.CreatedUnix.AsTime().Unix(), apiWatches[0].Created.Unix())
+		assert.EqualValues(t, issue.Index, apiWatches[0].IssueIndex)
+		assert.EqualValues(t, issue.Title, apiWatches[0].IssueTitle)
+		assert.EqualValues(t, repo.Name, apiWatches[0].RepoName)
+		assert.EqualValues(t, repo.OwnerName, apiWatches[0].RepoOwnerName)
+		assert.Greater(t, int64(apiWatches[0].Seconds), int64(0))
+	}
+}