feat: add i18n, platform channels page, and WeChat QR login

- Add vue-i18n with auto-detect browser language and manual toggle (EN/中文)
- Move platform channels to separate page with credential management
- Support Telegram, Discord, Slack, WhatsApp, Matrix, Feishu, Weixin, WeCom
- Add WeChat QR code login (opens in browser, polls status, auto-saves)
- Write platform credentials to ~/.hermes/.env matching hermes gateway setup
- Auto restart gateway after platform config changes
- Add settings store with per-section save for all config categories
- Persist session group collapse state across navigation
- Fix pre-existing TypeScript build errors

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/settings/PrivacySettings.vue

@@ -0,0 +1,35 @@
+<script setup lang="ts">
+import { NSwitch, useMessage } from 'naive-ui'
+import { useI18n } from 'vue-i18n'
+import { useSettingsStore } from '@/stores/settings'
+import SettingRow from './SettingRow.vue'
+
+const settingsStore = useSettingsStore()
+const message = useMessage()
+const { t } = useI18n()
+
+async function save(values: Record<string, any>) {
+  try {
+    await settingsStore.saveSection('privacy', values)
+    message.success(t('settings.saved'))
+  } catch (err: any) {
+    message.error(t('settings.saveFailed'))
+  }
+}
+</script>
+
+<template>
+  <section class="settings-section">
+    <SettingRow :label="t('settings.privacy.redactPii')" :hint="t('settings.privacy.redactPiiHint')">
+      <NSwitch :value="settingsStore.privacy.redact_pii" @update:value="v => save({ redact_pii: v })" />
+    </SettingRow>
+  </section>
+</template>
+
+<style scoped lang="scss">
+@use '@/styles/variables' as *;
+
+.settings-section {
+  margin-top: 16px;
+}
+</style>