feat(studio): show validity repair workflow state

[w1ne]

Summary

• add a shell-store workflow record for active Validity repair cards
• show Drafted, Running, Rechecked/Fixed, and Rechecked/Still failing states in Validity cards/summaries
• guard against false recheck labels before a submitted run, target changes, hidden still-present failures, and failed agent submissions

Verification

• npm test -- --run src/studio/tests/shellStore.test.ts src/studio/tests/tabs/ValidityTab.test.tsx src/studio/tests/StudioGenerate.test.tsx
• npm run typecheck
• npm run build:studio
• npm run lint (passes with existing unused-disable warnings outside touched files)