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-TW.ts

@@ -1481,7 +1481,7 @@ export const dict: Record<I18nKey, string> = {
   'chat.commandAutocomplete.command.timelineDescription': '開啟對話時間線',
   'chat.commandAutocomplete.command.compactDescription': '使用 AI 壓縮會話歷史以減少上下文大小',
   'chat.commandAutocomplete.command.summaryDescription': '非破壞性會話總結。命令後可選填主題提示。',
-  'chat.commandAutocomplete.command.workspaceReviewDescription': '僅審查目前工作區中高價值的問題。',
+  'chat.commandAutocomplete.command.workspaceReviewDescription': '審查工作區 diff 的意圖、正確性與充分性，並依嚴重程度分級。',
   'chat.commandAutocomplete.command.featurePlanDescription': '為新功能開始一次引導式的來回規劃工作階段。',
   'chat.commandAutocomplete.command.catchUpDescription': '重新進入上下文：你之前在做什麼、從哪裡繼續。',
   'chat.commandAutocomplete.command.debugDescription': '在提出修復方案前，引導式地排查 bug 的根本原因。',