feat: multi-language interface (zh-CN/zh-TW/en/ja), multilingual offline changelog, settings robustness

i18n
- shared/i18n: dependency-free t() with flat per-namespace dictionaries
  (common/settings/workspace/terminal/ssh/panels/main), zh-CN fallback
- language picker in Settings -> System; antd ConfigProvider locale follows it
- main process tracks the language too: tray menu, close prompt, ssh/sftp/
  zmodem errors and the log TUI marker are translated; tray rebuilds on change

changelog
- CHANGELOG.md (zh-CN canonical) + .zh-TW/.en/.ja, bundled via ?raw and read
  per interface language with per-version fallback to zh-CN (no network)
- sync-changelog.cjs merges RELEASE_NOTES[.<lang>].md per release; release.cjs
  refuses to publish without a zh-CN entry for the version

settings robustness
- closeAction 'ask' survives the sanitizer (was silently coerced to 'tray',
  which made the 'ask every time' option dead)
- highlight rules are repaired instead of dropped: string priority, 0/1
  enabled, missing fg colour; unknown fields preserved
- load-time warnings are written to settings-warnings.log (deduped, capped)

terminal/UI
- configurable terminal toolbar: open working directory (default on), session
  log recording (off), open logs folder (off)
- global shortcut field records key combos (modifier or F-key required)
- input suggestions + command history default to off, with a one-time reset
  migration for existing installs
- settings dialog scrolling fixed (antd v6 renamed the tabs container), theme
  gallery nested scrollbar removed, joined segmented pickers with readable
  selected-state text

tests: settings-store.mjs (15 checks) added; commands-store.mjs updated for
the new off-by-default history setting

src/main/updater.ts

@@ -1,6 +1,7 @@
 import { app, ipcMain, net, session } from 'electron'
 import { autoUpdater } from 'electron-updater'
 import { Ipc, type ReleaseNote, type UpdateState } from '../shared/ipc'
+import { t } from '../shared/i18n'
 import { broadcast } from './broadcast'
 import { loadSettings } from './settingsStore'
 import { markQuitting } from './tray'
@@ -77,7 +78,7 @@ async function checkWithFallback(): Promise<void> {
       await autoUpdater.checkForUpdates()
     } catch (err2) {
       const ghErr = err2 instanceof Error ? err2.message : String(err2)
-      throw new Error(`国内源: ${giteaErr}；GitHub: ${ghErr}`)
+      throw new Error(t('main.updater.feedFailed', { gitea: giteaErr, github: ghErr }))
     }
   }
 }