fix(ask): require multiSelect in schema and add desktop multi-select badge / 修复 ask 多选只能单选的问题

[JesonChou]

Summary

Fix #7649

When the ask tool presented a multi-pick question, the desktop UI appeared to accept multiple selections but actually replaced each pick with the last — silently restricting the user to a single choice. This happened because multiSelect was optional in the schema and the model frequently omitted it.

Root causes

• multiSelect was not required. The tool schema's question-level required array listed only ["question","header","options"], so the model could legally omit multiSelect. When omitted, Go defaulted it to false and the frontend received undefined (falsy), which triggered the single-select replace branch in toggleOption:

  { ...sel, [question.id]: [label] } ← replaces the entire selection

• No visual indication. The desktop AskCard had no checkbox, badge, or label telling the user whether the current question was multi-select or single-select.

Changes

File	Change
internal/agent/ask.go	Add multiSelect to the question-level required array; strengthen Description and field description to warn about consequences of omission
desktop/frontend/src/components/AskCard.tsx	Render a "可多选" / "Multi-select" badge in the header when q.multi is true
desktop/frontend/src/locales/zh.ts	Add "ask.multiSelectBadge": "可多选"
desktop/frontend/src/locales/en.ts	Add "ask.multiSelectBadge": "Multi-select"
desktop/frontend/src/locales/zh-TW.ts	Add "ask.multiSelectBadge": "可多選"
internal/agent/ask_test.go	Update provider contract hash after schema change
internal/boot/testdata/golden/*	Regenerate baseline files (system_prompt, tool_schemas, provider_request, prefix_shape)

Verification

Automated

• gofmt -l → OK
• go vet ./internal/agent/ → OK
• go test ./internal/agent/ -run Ask → 11/11 PASS
• go test ./internal/boot/ -count=1 → PASS

Manual (desktop)

• Confirmed multi-select AskCard shows the badge when multiSelect: true.
• Confirmed multi-select toggleOption accumulates picks correctly.
• Confirmed single-select badge is absent.

Compatibility

Area	Existing-data behavior	Conclusion
ask tool schema	multiSelect was optional; now required — model must always provide a boolean	Backward-compatible (existing calls that omit multiSelect will now fail validation; the model learns the new schema immediately)
Desktop i18n	New ask.multiSelectBadge keys added to three locale files	Backward-compatible (new keys, no existing references)
Golden baselines	Regenerated to match new Description and schema	Expected drift, no functional impact

Cache impact

Cache-impact: high — ask tool schema and description changed; golden system_prompt.txt, tool_schemas.json, provider_request.json, and prefix_shape.json all drift. The model-facing prompt prefix will change on the first turn after this merges.

Cache-guard: go test ./internal/agent/ -run Ask -count=1, go test ./internal/boot/ -count=1

System-prompt-review: @esengine — schema required-array change and tool description increase prompt token count slightly; verify prefix cache budget.

[zhefengzhang]

@SivanCola