Refactor frontend tw-justify-between layouts to flex-left-right (#37291)

This PR standardizes left/right two-child frontend layouts on
`flex-left-right` and removes ad-hoc `tw-justify-between` combinations.
The goal is consistent wrapping + spacing behavior under narrow widths
with less utility-class churn.

Also: remove useless "flex-center-wrap", slightly improve some templates
(no visual change, tested)

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: wxiaoguang <2114189+wxiaoguang@users.noreply.github.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/repo/actions/list.tmpl

@@ -25,7 +25,7 @@
 				</div>
 			</div>
 			<div class="flex-container-main">
-				<div class="ui top attached header flex-text-block tw-flex-wrap tw-justify-between">
+				<div class="ui top attached header flex-left-right">
 					<strong>{{ctx.Locale.TrN .Page.Paginater.Total "actions.runs.workflow_run_count_1" "actions.runs.workflow_run_count_n" .Page.Paginater.Total}}</strong>
 					<div class="ui secondary filter menu flex-text-block tw-m-0">
 						<!-- Actor -->

templates/repo/actions/workflow_dispatch.tmpl

@@ -1,5 +1,5 @@
 {{/* "z-index" is used to maintain continuous attached styling and keep the colored border-bottom visible (pre-existing fomantic issue with negative margins) */}}
-<div class="ui blue info attached message flex-text-block tw-flex-wrap tw-justify-between tw-z-1">
+<div class="ui blue info attached message flex-left-right tw-z-1">
 	<span>{{ctx.Locale.Tr "actions.workflow.has_workflow_dispatch"}}</span>
 	<div class="flex-text-block tw-bg-box-body tw-rounded">{{/*make the button have correct hovered color */}}
 		<button class="ui mini button show-modal" data-modal="#runWorkflowDispatchModal">{{ctx.Locale.Tr "actions.workflow.run"}}{{svg "octicon-triangle-down" 14 "dropdown icon"}}</button>