fix(macos): preserve native clipboard shortcuts

[tocekuma]

What and why

The Electron main process currently removes the entire application menu on every platform. On macOS, standard text-editing shortcuts such as Command+C, Command+V, Command+X, and Command+A are dispatched through native menu roles, so removing the menu can leave settings fields without working clipboard shortcuts.

This PR keeps only the native app and Edit menus on macOS. Windows and Linux retain the current hidden-menu behavior.

Linked Issue for product-semantic or public-contract changes: none (routine platform fix)

Change class

• Routine fix, documentation, test, maintenance, or presentation-only UI
• Product-semantic or public-contract change discussed in the linked Issue
• Isolated, default-off experiment

Owning layer: Electron application menu initialization

User-visible effect, or none: macOS users can use the standard Command-key clipboard and selection shortcuts in editable fields, including provider API-key inputs.

Compatibility or migration impact, or none: No migration. Other desktop platforms are unchanged.

Evidence

Commands and manual journeys run:

• npm test — 6 passed

• npm run build — passed

• git diff --check — passed

• Relevant Python tests pass

• CPU/model-less baseline remains supported

• Electron npm run build passes when Electron code changed

• Dependency audit passes when dependencies changed

• Before/after screenshots are attached for visible UI changes

• Documentation/examples are updated for changed settings or contracts

Final check

• This PR addresses one coherent problem without unrelated cleanup
• It does not add a speculative API, fallback, or compatibility path
• No secrets, local state, model weights, voice material, or restricted assets are included
• Third-party notices and provenance are preserved

[Lucas1479]

审查通过。appMenu + editMenu 使用 Electron 原生 role 恢复 macOS 标准编辑快捷键，Windows/Linux 仍返回 null，改动位于现有应用菜单所有者，没有引入额外平台分支。

我复核了 npm test（6 项通过）、npm run build 和 git diff --check。该修复可以独立批准；本次批准不执行合并。

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English

Approved. The native Electron appMenu and editMenu roles restore the standard macOS editing shortcuts, while Windows and Linux continue to return null. The change is located at the existing application-menu owner and does not add a parallel platform path.

I reran npm test (6 passed), npm run build, and git diff --check. This routine fix can be approved independently; this approval does not merge the PR.