fix: set privacy return real error

[PA733]

设置隐私时，后端会返回错误详情，前端会显示真正的设置结果（而不是原先始终的“操作成功”）

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[PA733]

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[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR improves the admin “Set Privacy” flow by returning richer backend error context (reason/stage/status/detail), surfacing that context in the frontend, and adding a dedicated success i18n key.

Changes:

• Add a PrivacySetResult structure and “Detailed” privacy-setting methods to propagate failure reasons/stages across services/handlers.
• Update the admin account privacy endpoint to return structured error details/metadata on failure.
• Enhance the admin UI to format/privacy failure messages using API error metadata; add new i18n success string.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
frontend/src/views/admin/AccountsView.vue	Formats privacy set success/failure UX; pulls structured API error metadata into UI messaging.
frontend/src/utils/apiError.ts	Allows extracting metadata from response.data.metadata in addition to top-level err.metadata.
frontend/src/i18n/locales/en.ts	Adds privacySetSuccess string for improved success messaging.
frontend/src/i18n/locales/zh.ts	Adds privacySetSuccess string for improved success messaging.
backend/internal/service/openai_privacy_service.go	Introduces PrivacySetResult and detailed OpenAI privacy setting results (reason/stage/detail).
backend/internal/service/antigravity_privacy_service.go	Introduces detailed Antigravity privacy setting results (reason/stage/detail).
backend/internal/service/admin_service.go	Adds ForceOpenAIPrivacyDetailed / ForceAntigravityPrivacyDetailed to the admin service interface and implementation.
backend/internal/handler/admin/admin_service_stub_test.go	Updates admin service test stub to satisfy the expanded interface.
backend/internal/handler/admin/account_handler.go	Returns ErrorWithDetails for privacy failures, including structured metadata for the frontend.

Comments suppressed due to low confidence (1)

backend/internal/service/antigravity_privacy_service.go:1

• The docstring states that an empty string indicates 'cannot execute'. After introducing the detailed result, ensure this comment stays accurate for all precheck conditions (notably missing projectID, which should align with the 'cannot execute' semantics). If you keep any precheck returning a non-empty failure mode, update this comment accordingly.

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