enhance(repo): unify diff stats on commit pages, misc diff tweaks (#39134)

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

routers/web/repo/commit.go

@@ -395,6 +395,8 @@ func Diff(ctx *context.Context) {
 	ctx.Data["CommitOtherParticipants"] = gituser.BuildAvatarStackData(ctx, commit.CoAuthorIdentities(), nil).Participants
 	ctx.Data["Parents"] = parents
 	ctx.Data["DiffNotAvailable"] = diffShortStat.NumFiles == 0
+	ctx.Data["ShowDiffSummaryInToolbar"] = false
+	ctx.Data["ShowDiffSummaryInCommitHeader"] = diffShortStat.NumFiles != 0
 
 	if err := asymkey_model.CalculateTrustStatus(verification, ctx.Repo.Repository.GetTrustModel(), func(user *user_model.User) (bool, error) {
 		return repo_model.HasAccessToRepoCodeUnit(ctx, ctx.Repo.Repository, user.ID)

routers/web/repo/compare.go

@@ -438,6 +438,7 @@ func (cpi *comparePageInfoType) prepareCompareDiff(ctx *context.Context, whitesp
 		AfterCommitID: headCommitID,
 	}
 	ctx.Data["DiffNotAvailable"] = diffShortStat.NumFiles == 0
+	ctx.Data["ShowDiffSummaryInToolbar"] = diffShortStat.NumFiles != 0
 
 	if !fileOnly {
 		diffTree, err := gitdiff.GetDiffTree(ctx, ci.HeadGitRepo, false, beforeCommitID, headCommitID)

routers/web/repo/pull.go

@@ -871,6 +871,7 @@ func viewPullFiles(ctx *context.Context, beforeCommitID, afterCommitID string) {
 		AfterCommitID:  afterCommitID,
 	}
 	ctx.Data["DiffNotAvailable"] = diffShortStat.NumFiles == 0
+	ctx.Data["ShowDiffSummaryInToolbar"] = diffShortStat.NumFiles != 0
 
 	if ctx.Data["CanMarkConversation"], err = issues_model.CanMarkConversation(ctx, issue, ctx.Doer); err != nil {
 		ctx.ServerError("CanMarkConversation", err)