feat: multi-OpenClaw CLI detection/binding + i18n infrastructure

Multi-OpenClaw Detection & Binding:
- Add resolve_openclaw_cli_path() and classify_cli_source() in utils.rs
- Support openclawCliPath binding in clawpanel.json (user selects CLI)
- VersionInfo now includes cli_path, cli_source, all_installations
- scan_all_installations() detects all OpenClaw installs on system
- Dashboard shows CLI source label + multi-install warning
- Settings page: CLI binding UI with auto-detect and manual selection
- dev-api.js synced with cli_path/cli_source fields for Web mode

i18n Infrastructure:
- Create src/lib/i18n.js core module (t(), setLang(), initI18n())
- Create src/locales/zh-CN.json and src/locales/en.json
- Sidebar fully i18n-ized (nav labels, sections, instance switcher)
- Dashboard stat cards fully i18n-ized
- Settings page: language switcher UI (live reload)
- initI18n() called in main.js on startup

src/lib/i18n.js

@@ -0,0 +1,89 @@
+/**
+ * i18n 国际化核心模块
+ * 支持中文(zh-CN)和英文(en)，按需扩展
+ */
+import zhCN from '../locales/zh-CN.json'
+import en from '../locales/en.json'
+
+const LANGS = { 'zh-CN': zhCN, en }
+const LANG_KEY = 'clawpanel_lang'
+const FALLBACK = 'zh-CN'
+
+let _lang = FALLBACK
+let _dict = zhCN
+let _listeners = []
+
+/**
+ * 翻译函数
+ * @param {string} key - 点分隔路径，如 'sidebar.dashboard'
+ * @param {object} [params] - 插值参数，如 { count: 3 } 替换 {count}
+ * @returns {string}
+ */
+export function t(key, params) {
+  let val = _resolve(_dict, key)
+  if (val === undefined) {
+    // fallback 到中文
+    val = _resolve(zhCN, key)
+  }
+  if (val === undefined) return key
+  if (params) {
+    for (const [k, v] of Object.entries(params)) {
+      val = val.replace(new RegExp(`\\{${k}\\}`, 'g'), String(v))
+    }
+  }
+  return val
+}
+
+function _resolve(obj, path) {
+  const parts = path.split('.')
+  let cur = obj
+  for (const p of parts) {
+    if (cur == null || typeof cur !== 'object') return undefined
+    cur = cur[p]
+  }
+  return typeof cur === 'string' ? cur : undefined
+}
+
+/** 获取当前语言 */
+export function getLang() { return _lang }
+
+/** 获取所有可用语言 */
+export function getAvailableLangs() {
+  return [
+    { code: 'zh-CN', label: '简体中文' },
+    { code: 'en', label: 'English' },
+  ]
+}
+
+/** 切换语言 */
+export function setLang(lang) {
+  if (!LANGS[lang]) return
+  _lang = lang
+  _dict = LANGS[lang]
+  localStorage.setItem(LANG_KEY, lang)
+  _listeners.forEach(fn => { try { fn(lang) } catch {} })
+}
+
+/** 监听语言变化 */
+export function onLangChange(fn) {
+  _listeners.push(fn)
+  return () => { _listeners = _listeners.filter(cb => cb !== fn) }
+}
+
+/** 初始化：localStorage > navigator.language > fallback */
+export function initI18n() {
+  const saved = localStorage.getItem(LANG_KEY)
+  if (saved && LANGS[saved]) {
+    _lang = saved
+    _dict = LANGS[saved]
+    return
+  }
+  // 自动检测浏览器语言
+  const nav = navigator.language || navigator.languages?.[0] || ''
+  if (nav.startsWith('zh')) {
+    _lang = 'zh-CN'
+  } else if (nav.startsWith('en')) {
+    _lang = 'en'
+  }
+  _dict = LANGS[_lang] || zhCN
+}