Fix timeline event layout overflow with long content (#36595)

Fixes: https://github.com/go-gitea/gitea/issues/36580

Bug is caused by abuse of float layout, convert layout to flex to fix
it. There are more float abuses, but this shouldn't cause any other
regressions.

Before:

<img width="939" height="165" alt="Screenshot 2026-02-12 at 06 22 45"
src="https://github.com/user-attachments/assets/3e0aea82-d31e-4f4f-97d1-903b9f34de8d"
/>

After:

<img width="961" height="191" alt="image"
src="https://github.com/user-attachments/assets/b8fa64dc-594f-46a6-87e4-c20475e7d1e8"
/>

---------

Signed-off-by: silverwind <me@silverwind.io>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

templates/repo/issue/view_content/comments_delete_time.tmpl

@@ -1,7 +1,7 @@
 {{if and .comment.Time (.ctxData.Repository.IsTimetrackerEnabled ctx)}} {{/* compatibility with time comments made before v1.14 */}}
 	{{if (not .comment.Time.Deleted)}}
 		{{if (or .ctxData.IsAdmin (and .ctxData.IsSigned (eq .ctxData.SignedUserID .comment.PosterID)))}}
-			<span class="tw-float-right">
+			<span class="tw-ml-auto">
 				<button class="ui icon button compact mini link-action" data-tooltip-content="{{ctx.Locale.Tr "repo.issues.del_time"}}"
 								data-url="{{.ctxData.RepoLink}}/issues/{{.ctxData.Issue.Index}}/times/{{.comment.TimeID}}/delete?id={{.comment.Time.ID}}"
 								data-modal-confirm="{{ctx.Locale.Tr "repo.issues.del_time"}}"