Summary

This PR fixes the add-menu tooltip in the desktop composer.

It does three things:

• restores tooltip hover/focus behavior without leaking hover state from the outer composer container
• ensures the desktop renderer emits the shared tooltip's Tailwind classes by explicitly sourcing packages/ui/src
• adds the missing localized tooltip labels for the add-menu trigger in both en and zh-CN

Problem

From the user’s perspective, the bug showed up in two ways:

• moving the mouse over the prompt input area incorrectly triggered the add-menu tooltip even when the + trigger itself was not being hovered
• when the tooltip appeared, it was visually broken: it looked like a white floating block and the text was not readable

How to Reproduce

1. Create a new design.
2. Move the mouse over the prompt input area in the lower-left composer.
3. Observe that the add-menu tooltip is triggered even though the pointer is not on the + trigger.

Root Cause

The add-menu tooltip regressed for two separate reasons:

1. The shared Tooltip component stopped using an isolated hover scope, which made the composer and tooltip hover behavior interfere with each other.
2. The desktop renderer's Tailwind source detection was not scanning packages/ui/src, so the shared tooltip's named group variants were not emitted into the app CSS.
3. The sidebar.chat.addMenu.trigger translation key was missing, so the add-menu trigger had no proper user-facing tooltip label.

What Changed

Tooltip behavior

• switched the shared Tooltip component back to named Tailwind groups via group/tooltip
• restored the corresponding hover/focus visibility classes:
  • group-hover/tooltip:opacity-100
  • group-focus-within/tooltip:opacity-100
  • group-focus/tooltip:opacity-100
• updated the shared tooltip test assertions to match the named-group implementation

Tailwind source detection

• added an explicit Tailwind @source entry in the desktop renderer CSS so the renderer build scans packages/ui/src
• this ensures shared UI component classnames are included in the generated desktop CSS

i18n

• added sidebar.chat.addMenu.trigger in en
• added sidebar.chat.addMenu.trigger in zh-CN

DCO

• added a signed-off follow-up commit so the current DCO workflow passes without rewriting the earlier fix commits

User Impact

• hovering the + add-menu trigger shows a tooltip again
• hovering the prompt textarea no longer causes tooltip leakage from the nested add-menu control
• the tooltip now has proper localized text instead of relying on a missing translation key

Validation

• turbo run test via the repository commit hook
• pnpm --filter @open-codesign/ui test -- Tooltip
• pre-push workspace checks:
  • typecheck
  • lint

Principles §5b

• Compatibility: ✅ No schema, storage, or IPC contract changes.
• Upgradeability: ✅ Localized UI-only fix with no migration risk.
• No bloat: ✅ No new dependencies or runtime subsystems.
• Elegance: ✅ Uses scoped Tailwind groups and explicit source detection instead of extra JS or ad-hoc DOM workarounds.