feat: strengthen /workspace-review beyond high-signal-only

The old workspace-review prompt only hunted for catastrophic bugs and
omitted everything it wasn't highly certain about, so it usually returned
'No high-signal issues found' and felt useless.

Rework it to first understand the diff's intent and judge whether the
implementation actually achieves it and is adequate (smallest correct
solution, completeness), then review correctness across concrete failure
modes (concurrency, lifecycle, state fanout, comparators, a11y,
regressions, targeted-test gaps) plus a security/supply-chain lens, and
classify findings by severity (blocker / non-blocker / nit). Keeps the
existing false-positive discipline (diff is source of truth, validation
pass, no nitpicks, cite rules) and stays review-only by default.

Adapted from a battle-tested PR-review prompt, minus the GitHub-specific
parts that don't apply to a local workspace diff. Updates command and
settings descriptions across locales.

packages/ui/src/lib/i18n/messages/zh-CN.ts

@@ -1484,7 +1484,7 @@ export const dict: Record<I18nKey, string> = {
   'chat.commandAutocomplete.command.timelineDescription': '打开对话时间线',
   'chat.commandAutocomplete.command.compactDescription': '使用 AI 压缩会话历史以减少上下文大小',
   'chat.commandAutocomplete.command.summaryDescription': '非破坏性会话总结。命令后可选填主题提示。',
-  'chat.commandAutocomplete.command.workspaceReviewDescription': '仅审查当前工作区中高价值的问题。',
+  'chat.commandAutocomplete.command.workspaceReviewDescription': '审查工作区 diff 的意图、正确性与充分性，并按严重程度分级。',
   'chat.commandAutocomplete.command.featurePlanDescription': '为新功能开始一次引导式的来回规划会话。',
   'chat.commandAutocomplete.command.catchUpDescription': '重新进入上下文：你之前在做什么、从哪里继续。',
   'chat.commandAutocomplete.command.debugDescription': '在提出修复方案前，引导式地排查 bug 的根本原因。',