feat(auth): 后台登录、角色权限与会话访问策略

管理员与客服分角色登录，权限由后端判定；前端补齐登录、人员与组织管理页面。

frontend/src/components/common/ChannelBadge.vue

@@ -0,0 +1,58 @@
+<!--
+Copyright 2024-2026 ChatterMate
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+
+<script setup lang="ts">
+import { computed } from 'vue'
+
+const props = defineProps<{
+  channel?: string | null
+}>()
+
+const CHANNEL_LABELS: Record<string, string> = {
+  shopify: 'Shopify',
+  telegram: 'Telegram',
+  whatsapp: 'WhatsApp',
+  messenger: 'Messenger',
+  instagram: 'Instagram',
+  slack: 'Slack',
+  email: 'Email',
+  sms: 'SMS',
+  line: 'LINE',
+  api: 'API',
+}
+
+// The widget ('web') is the default context — no badge needed for it.
+const label = computed(() => (props.channel ? CHANNEL_LABELS[props.channel] : null))
+</script>
+
+<template>
+  <span v-if="label" class="channel-badge" :class="`channel-${channel}`">{{ label }}</span>
+</template>
+
+<style scoped>
+.channel-badge {
+  display: inline-flex;
+  align-items: center;
+  padding: 1px 8px;
+  border-radius: var(--radius-chip, 999px);
+  font-size: 11px;
+  font-weight: 600;
+  line-height: 1.6;
+  background: var(--accent-bg-12, rgba(59, 130, 246, 0.12));
+  color: var(--accent-ink, #2563eb);
+  white-space: nowrap;
+}
+</style>