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

scripts/sync-changelog.cjs

@@ -1,39 +1,62 @@
-/* Merge RELEASE_NOTES.md into CHANGELOG.md as the section for the current
-   package.json version. Idempotent: skips if the version is already present.
-   Run BEFORE `npm run dist` — the changelog is bundled into the app.
-   Usage: node scripts/sync-changelog.cjs */
+/* Merge per-language release notes into the matching CHANGELOG file as the
+   section for the current package.json version. Idempotent: a version already
+   present is skipped. Run BEFORE `npm run dist` — the changelogs are bundled
+   into the app and shown per interface language.
+   Usage: node scripts/sync-changelog.cjs
+
+   RELEASE_NOTES.md (Simplified Chinese) is required; the other three are
+   optional — a version without a translation falls back to zh-CN in the UI. */
 const fs = require('node:fs')
 const path = require('node:path')
 
 const ROOT = path.join(__dirname, '..')
 const pkgVersion = JSON.parse(fs.readFileSync(path.join(ROOT, 'package.json'), 'utf8')).version
-const notesPath = path.join(ROOT, 'RELEASE_NOTES.md')
-const changelogPath = path.join(ROOT, 'CHANGELOG.md')
-const HEADER = '# OpenTerminal 更新日志'
 
-const notes = fs.readFileSync(notesPath, 'utf8')
-  // Drop the notes' own leading title / `## vX` heading — the section heading
-  // is constructed here so CHANGELOG stays uniform (`## vX.Y.Z - date`).
-  .replace(/^#.*\n/gm, '')
-  .replace(new RegExp(`^## v${pkgVersion}.*\\n`), '')
-  .replace(/^\s+/, '')
-  .trimEnd()
+const TARGETS = [
+  { notes: 'RELEASE_NOTES.md', changelog: 'CHANGELOG.md', header: '# OpenTerminal 更新日志', required: true },
+  { notes: 'RELEASE_NOTES.zh-TW.md', changelog: 'CHANGELOG.zh-TW.md', header: '# OpenTerminal 更新日誌' },
+  { notes: 'RELEASE_NOTES.en.md', changelog: 'CHANGELOG.en.md', header: '# OpenTerminal Changelog' },
+  { notes: 'RELEASE_NOTES.ja.md', changelog: 'CHANGELOG.ja.md', header: '# OpenTerminal 更新履歴' }
+]
 
-if (!notes) {
-  console.error('RELEASE_NOTES.md is empty — write release notes first')
-  process.exit(1)
+const sync = ({ notes, changelog, header, required }) => {
+  const notesPath = path.join(ROOT, notes)
+  const changelogPath = path.join(ROOT, changelog)
+  if (!fs.existsSync(notesPath)) {
+    if (required) {
+      console.error(`${notes} is missing — write the release notes first`)
+      process.exit(1)
+    }
+    console.log(`${changelog}: no ${notes} — left unchanged`)
+    return
+  }
+
+  const body = fs
+    .readFileSync(notesPath, 'utf8')
+    // Drop the notes' own title / `## vX` heading: the section heading is built
+    // here so every changelog stays uniform (`## vX.Y.Z - date`).
+    .replace(/^#.*\n/gm, '')
+    .replace(new RegExp(`^## v${pkgVersion}.*\\n`), '')
+    .replace(/^\s+/, '')
+    .trimEnd()
+
+  if (!body) {
+    console.error(`${notes} is empty — write the release notes first`)
+    process.exit(1)
+  }
+
+  const existing = fs.existsSync(changelogPath) ? fs.readFileSync(changelogPath, 'utf8') : ''
+  if (existing.includes(`## v${pkgVersion} `)) {
+    console.log(`${changelog}: already has v${pkgVersion} — nothing to do`)
+    return
+  }
+
+  const section = `## v${pkgVersion} - ${new Date().toISOString().slice(0, 10)}\n\n${body}\n`
+  const updated = existing
+    ? existing.replace(new RegExp(`^(${header}\\n\\n)`), `$1${section}\n`)
+    : `${header}\n\n${section}`
+  fs.writeFileSync(changelogPath, updated, 'utf8')
+  console.log(`${changelog}: added v${pkgVersion} (${body.split('\n').length} lines)`)
 }
 
-const section = `## v${pkgVersion} - ${new Date().toISOString().slice(0, 10)}\n\n${notes}\n`
-const existing = fs.existsSync(changelogPath) ? fs.readFileSync(changelogPath, 'utf8') : ''
-if (existing.includes(`## v${pkgVersion} `)) {
-  console.log(`CHANGELOG.md already has v${pkgVersion} — nothing to do`)
-  process.exit(0)
-}
-
-const updated = existing
-  ? existing.replace(new RegExp(`^(${HEADER}\\n\\n)`), `$1${section}\n`)
-  : `${HEADER}\n\n${section}`
-
-fs.writeFileSync(changelogPath, updated, 'utf8')
-console.log(`CHANGELOG.md: added v${pkgVersion} (${notes.split('\n').length} lines)`)
+for (const target of TARGETS) sync(target)